Ch3 – Metric Conversions
Ch3 – Metric Conversions
“King Henry David Usually drinks chocolate milk”
Giga . . Mega . . Kilo Hecta Deka Basic deci centi milli . . micro . . nano . . pico
Units
“King Henry David Usually drinks chocolate milk”
Giga . . Mega . . Kilo Hecta Deka Basic deci centi milli . . micro . . nano . . pico
Units
(Meters)
(Liters)
(Grams)
G .. M .. K H D U d c m .. μ .. n .. p
“King Henry David Usually drinks chocolate milk”
Giga . . Mega . . Kilo Hecta Deka Basic deci centi milli . . micro . . nano . . pico
Units
G .. M .. K H D U d c m .. μ .. n .. p
Exs:
505 grams = __________ kilograms
90 cm = __________ m
2.05 L = __________ mL
75 km = __________ m
75 nm = __________ m
700 μm = __________ m
Describing Motion
Describing Motion
Vectors –
Scalars –
Describing Motion
Vectors – describe things that have both magnitude and direction
Use arrows to represent them.
Scalars –
Describing Motion
Vectors – describe things that have both magnitude and direction
Use arrows to represent them.
Scalars – have only magnitude
Describing Motion
Vectors – describe things that have both magnitude and direction
Use arrows to represent them.
Scalars – have only magnitude
Examples:
1. Speed (v) –
vs.

2. Velocity ( v ) –
Describing Motion
Vectors – describe things that have both magnitude and direction
Use arrows to represent them.
Scalars – have only magnitude
Examples:
1. Speed (v) – how fast something is going
vs.

2. Velocity ( v ) –
Describing Motion
Vectors – describe things that have both magnitude and direction
Use arrows to represent them.
Scalars – have only magnitude
Examples:
1. Speed (v) – how fast something is going
vs.

2. Velocity ( v ) – how fast its going in a particular direction
Describing Motion
Vectors – describe things that have both magnitude and direction
Use arrows to represent them.
Scalars – have only magnitude
Examples:
1. Speed (v) – how fast something is going
vs.

2. Velocity ( v ) – how fast its going in a particular direction
1. Distance (d) –
vs.

2. Displacement (d ) –
Describing Motion
Vectors – describe things that have both magnitude and direction
Use arrows to represent them.
Scalars – have only magnitude
Examples:
1. Speed (v) – how fast something is going
vs.

2. Velocity ( v ) – how fast its going in a particular direction
1. Distance (d) – how far something moves
vs.

2. Displacement (d ) –
Describing Motion
Vectors – describe things that have both magnitude and direction
Use arrows to represent them.
Scalars – have only magnitude
Examples:
1. Speed (v) – how fast something is going
vs.

2. Velocity ( v ) – how fast its going in a particular direction
1. Distance (d) – how far something moves
vs.

2. Displacement (d ) – how far something moves in a particular
direction. (Straight line distance)
Displacement = velocity . time
d=v.t
Displacement = velocity . time
d=v.t
Measure velocity in:
miles per hour (mph)
Kilometers per hour (km/hr)
Meters per second (m/s)
Displacement = velocity . time
d=v.t
Measure velocity in:
miles per hour (mph)
Kilometers per hour (km/hr)
Meters per second (m/s)
Ex: A car passes a sign that reads 40.1 km while traveling east
thru a straight valley. 30 minutes later it passes a sign that reads
84.5 km. How fast was the car traveling? (Use m/s)
Ch3 HW#1 1-3 +
metric conversions
Ch3 HW#1
1. A desert tortoise covers 1.5 m in 45 sec. What is its speed?
2. A bicyclist travels 55 km in 1 hr 30 mins. Speed?
3. Car passes sign that reads 25.6 km traveling north. 1 hr 15 min later
it passes a sign that reads 115.2 km. Speed?
Metric Conv
1. 7 mm = _____ cm
2. 8.1 mm = _____ m
3. 8.2 mm = _____ km
4. 7.5 cm = _____ mm
5.
6.
7.
8.
6.3 cm = _____ m 9. 7.2 μ = _____ cm
3.3 cm = _____ km 10. 1.2 km = _____ nm
3.6 m = _____ km 11. 1.7 km = _____ cm
5.2 pm = _____ mm
Ch3 HW#1
1. A desert tortoise covers 1.5 m in 45 sec. What is its speed?
(d=vt)
d 1.5m
v
t

45 sec
 0.073m / s
2. A bicyclist travels 55 km in 1 hr 30 mins. Speed?
55 km = 55,000 m
1.5 hr 3600 sec
= 5400 sec
1 hr
3. Car passes sign that reads 25.6 km traveling north. 1 hr 15 min
later it passes a sign that reads 115.2 km. Speed?
d = 115.2 – 25.6 = 89.6 km = 89,600 m
1.25 hr 3600 sec = 4500 sec
1 hr
Ch3 HW#1
1. A desert tortoise covers 1.5 m in 45 sec. What is its speed?
(d=vt)
d 1.5m
v
t

45 sec
 0.073m / s
2. A bicyclist travels 55 km in 1 hr 30 mins. Speed?
55 km = 55,000 m
d 55,000m
v 
 10.2m / s
1.5 hr 3600 sec
= 5400 sec
t 5400 sec
1 hr
3. Car passes sign that reads 25.6 km traveling north. 1 hr 15 min
later it passes a sign that reads 115.2 km. Speed?
d = 115.2 – 25.6 = 89.6 km = 89,600 m
1.25 hr 3600 sec = 4500 sec
1 hr
Ch3 HW#1
1. A desert tortoise covers 1.5 m in 45 sec. What is its speed?
(d=vt)
d 1.5m
v
t

45 sec
 0.073m / s
2. A bicyclist travels 55 km in 1 hr 30 mins. Speed?
55 km = 55,000 m
d 55,000m
v 
 10.2m / s
1.5 hr 3600 sec
= 5400 sec
t 5400 sec
1 hr
3. Car passes sign that reads 25.6 km traveling north. 1 hr 15 min
later it passes a sign that reads 115.2 km. Speed?
d = 115.2 – 25.6 = 89.6 km = 89,600 m
1.25 hr 3600 sec = 4500 sec
1 hr
d 89,600m
v 
 19.9m / s
t 4500 sec
Ch3 HW#1
Metric Conv
G . . M . . KHDUdcm . . μ . . n . . p
1. 7 mm =
____ cm
2. 8.1 mm =
______ m
3. 8.2 mm =
________ km
4. 7.5 cm =
___mm
5.
6.
7.
8.
6.3 cm = _______ m
3.3 cm = ________ km
3.6 m = _______km
5.2 pm = ____________mm
9. 7.2 μm = _______ cm
10. 1.2 km = ______________nm
11. 1.7 km = ______ cm
Ch3 HW#1
Metric Conv
G . . M . . KHDUdcm . . μ . . n . . p
1. 7 mm =
0.07 cm
2. 8.1 mm =
0.0081 m
3. 8.2 mm =
0.0000082 km
4. 7.5 cm =
75 mm
5.
6.
7.
8.
6.3 cm = _______ m
3.3 cm = ________ km
3.6 m = _______km
5.2 pm = ____________mm
9. 7.2 μm = _______ cm
10. 1.2 km = ______________nm
11. 1.7 km = ______ cm
Ch3 HW#1
Metric Conv
G . . M . . KHDUdcm . . μ . . n . . p
1. 7 mm =
0.07 cm
2. 8.1 mm =
0.0081 m
3. 8.2 mm =
0.0000082 km
4. 7.5 cm =
75 mm
5.
6.
7.
8.
6.3 cm = 0.063 m
3.3 cm = 0.000033 km
3.6 m = 0.0036 km
5.2 pm = 0.000 000 0052 mm
9. 7.2 μm = _______ cm
10. 1.2 km = ______________nm
11. 1.7 km = ______ cm
Ch3 HW#1
Metric Conv
G . . M . . KHDUdcm . . μ . . n . . p
1. 7 mm =
0.07 cm
2. 8.1 mm =
0.0081 m
3. 8.2 mm =
0.0000082 km
4. 7.5 cm =
75 mm
5.
6.
7.
8.
6.3 cm = 0.063 m
3.3 cm = 0.000033 km
3.6 m = 0.0036 km
5.2 pm = 0.000 000 0052 mm
9. 7.2 μm = 0.00072 cm
10. 1.2 km = 12,000,000,000,000 nm
11. 1.7 km = 170,000 cm
Ch3.3 Velocity and Acceleration
Velocity – speed in a specific direction
Ch3.3 Velocity and Acceleration
Velocity – speed in a specific direction
Average velocity – since speed can vary in most cases,
use average speed.
- easiest method is finding total distance divided by total time
Ch3.3 Velocity and Acceleration
Velocity – speed in a specific direction
Average velocity – since speed can vary in most cases,
use average speed.
- easiest method is finding total distance divided by total time
d
v
t
Ch3.3 Velocity and Acceleration
Velocity – speed in a specific direction
Average velocity – since speed can vary in most cases,
use average speed.
- easiest method is finding total distance divided by total time
d
v
t
Instantaneous velocity – speed and direction at that moment
(GPS and speedometer in your car)
Ch3.3 Velocity and Acceleration
Velocity – speed in a specific direction
Average velocity – since speed can vary in most cases,
use average speed.
- easiest method is finding total distance divided by total time
d
v
t
Instantaneous velocity – speed and direction at that moment
(GPS and speedometer in your car)
Ex1) Standing on a roof 100m above the ground, a kid drops a water
balloon 4.5s it hits the ground. What was the average speed?
Ex2) Hair grows at an average rate of 3x10-9 m/s.
Find the length after one year.
Ex2) Hair grows at an average rate of 3x10-9 m/s.
Find the length after one year.
d = v.t
= (3x10-9m/s)(3.2x107s)
= 0.09m (9 cm)
What if the hair was already 10cm long before the year started,
how long would it be a year later?
To find distance when not starting at zero:
df = di + v.t
Ex3) A car passes a sign that reads 213.8km. If the cruise control is set
at 88km/hr, what does a sign read ½ hour later?
Acceleration – a measure of the change in velocity
v
a
t
speeding up: a = (+)
slowing down: a = (–)
Ex4) Set up only: A driver traveling at 25m/s slows at a constant rate
of 8.5m/s2. What is the total distance the car moves before stopping?
Ch3 HW#2 4 – 8
Lab3.1 – Motion
- due tomorrow
- go over Ch3 HW#2 @ beginning of period
Ch3 HW#2 4 – 8 (Set up, no solve, except 8)
4. A dragster starting from rest accelerates at 49 m/s2.
How fast is it going when it has traveled 325m?
5. The same dragster reaches the end of the drag strip rolling at 100km/hr,
when it opens its parachute. It rolls to a stop in 150m.
How much time does it take to come to a stop?
6. A ball is thrown upward at 25m/s. Gravity slows it at 10m/s2.
What height does it reach?
7. A ball is hit and then slowly comes to a stop in 5 sec.
Draw. When is it going fastest? What is its final speed?
Is its accl +/-?
8. Solve: Enter a toll road at 1pm. After traveling 55km, the ticket
is stamped 2:30pm. What was the average speed.
At any time could it have been going faster than the average?
Why speed not velocity?
Ch 4 - Vectors
-Have magnitude (length) and point in a direction
Ch 4 - Vectors
-Have magnitude (length) and point in a direction
Ex1) Draw vectors representing velocities:
15 m/s North
10 m/s East
Vectors can be added together, called vector addition
Vectors can be added together, called vector addition
- Graphically, place them head to tail
Vectors can be added together, called vector addition
- Graphically, place them head to tail
- Mathematically, vector addition means 3 possibilities:
Vectors can be added together, called vector addition
- Graphically, place them head to tail
- Mathematically, vector addition means 3 possibilities:
1. Point same direction: Add
2. Point opposite directions: Subtract
3. Point perpendicular: Pythag
Ex2) Vector Addition:
a) 2 km east and 1 km east
b) 3 km east and 2 km west
c) 3 km north and 4 km east
Ex2) Vector Addition:
a) 2 km east and 1 km east
2km
(Red is the
resultant vector)
1km
2 + 1 = 3 km
3km
b) 3 km east and 2 km west
1km 2km
3–2=1
(Red is the
resultant vector)
4km
c) 3 km north and 4 km east
32  42  5km
3km
5 km
(Red is the resultant vector)
--The order you add vectors doesn’t matter
HW#2) A shopper walks from the door of the mall to her car 250 m down
a lane of cars, then turns 90° to the right and walks an additional 60 m.
What is the magnitude of the displacement of her car from the mall door?
HW#2) A shopper walks from the door of the mall to her car 250 m down
a lane of cars, then turns 90° to the right and walks an additional 60 m.
What is the magnitude of the displacement of her car from the mall door?
60
250
Mall
d = √ 250 +60
= 257m
2
2
3. A boat is rowed South at 3 m/s down a river that flows South at 5 m/s.
What speed does an observer from shore see the boat moving?
-A boat is rowed North at 3 m/s up a river that flows South at 5 m/s.
What speed does an observer from shore see the boat moving?
-A boat is rowed East at 3 m/s across a river that flows South at 5 m/s.
What speed does an observer from shore see the boat moving?
3. A boat is rowed South at 3 m/s down a river that flows South at 5 m/s.
What speed does an observer from shore see the boat moving?
3m/s
5m/a
8m/s
-A boat is rowed North at 3 m/s up a river that flows South at 5 m/s.
What speed does an observer from shore see the boat moving?
-A boat is rowed East at 3 m/s across a river that flows South at 5 m/s.
What speed does an observer from shore see the boat moving?
3. A boat is rowed South at 3 m/s down a river that flows South at 5 m/s.
What speed does an observer from shore see the boat moving?
3m/s
8m/s
5m/a
-A boat is rowed North at 3 m/s up a river that flows South at 5 m/s.
What speed does an observer from shore see the boat moving?
3
5
2m/s
-A boat is rowed East at 3 m/s across a river that flows South at 5 m/s.
What speed does an observer from shore see the boat moving?
3. A boat is rowed South at 3 m/s down a river that flows South at 5 m/s.
What speed does an observer from shore see the boat moving?
3m/s
8m/s
5m/a
-A boat is rowed North at 3 m/s up a river that flows South at 5 m/s.
What speed does an observer from shore see the boat moving?
3
5
2m/s
-A boat is rowed East at 3 m/s across a river that flows South at 5 m/s.
What speed does an observer from shore see the boat moving?
v = √ 32 +52
3
5
v = 5.8m/s
Θ
HW#8. An airplane flies due north at 150 km/h with respect to the air.
There is a wind blowing at 75 km/h to the east relative to the ground.
What is the plane’s speed with respect to the ground?
Ch4 HW#1 1 – 8
HW#8. An airplane flies due north at 150 km/h with respect to the air.
There is a wind blowing at 75 km/h to the east relative to the ground.
What is the plane’s speed with respect to the ground?
75 km/hr
150 km/hr
v = √ 1502 + 752 = 167.7 km/hr
Ch4 HW#1 1 – 8
Lab3.2 More Motion
- due tomorrow (in school terms)
- Ch4 HW#1 due at the beginning of the period
Ch4 HW #1 1 – 8
1. A car is driven 125 km due west, then 65km due south. What is the
magnitude of its displacement?
2. (In class)
Ch4 HW #1 1 – 8
1. A car is driven 125 km due west, then 65km due south. What is the
magnitude of its displacement?
125 km
65 km
2. (In class)
d = √1252 + 652
= 141 km
3. In class
4. A car moving east at 45 km/hr for 1 hour turns and travels north at 30
km/hr for 2 hours. What are the magnitude of its displacement?
5. You are riding in a bus moving slowly through heavy traffic at 2.0 m/s. You
hurry to the front of the bus at 4.0 m/s relative to the
bus. What is your speed relative to the street?
3. In class
4. A car moving east at 45 km/hr for 1 hour turns and travels north at 30
km/hr for 2 hours. What are the magnitude of its displacement?
d=v∙t
= (30km/hr)(2hr)
= 60km
60 km
d = √452 + 602
45 km
5. You are riding in a bus moving slowly through heavy traffic at 2.0 m/s.
You hurry to the front of the bus at 4.0 m/s relative to the bus.
What is your speed relative to the street?
2
4
d=2+4
= 6 m/s
6. A motorboat heads due east at 11 m/s relative to the water across a river
that flows due north at 5.0 m/s. What is the velocity of the motorboat with
respect to the shore?
5m/s
11m/s
7. A person walks 3 blocks north, turns and walks 2 blocks east, turns and
walks 4 more blocks north, and finally turns east and walks 2 more blocks east.
In terms of city blocks, how far is the person from where they started? (Hint:
vectors can be added in any order. Maybe you can switch the order so that they
make a triangle to pythag.)
8. In class
6. A motorboat heads due east at 11 m/s relative to the water across a river
that flows due north at 5.0 m/s. What is the velocity of the motorboat with
respect to the shore?
5m/s
11m/s
7. A person walks 3 blocks north, turns and walks 2 blocks east, turns and
walks 4 more blocks north, and finally turns east and walks 2 more blocks east.
In terms of city blocks, how far is the person from where they started? (Hint:
vectors can be added in any order. Maybe you can switch the order so that they
make a triangle to pythag.)
4 blocks E
7 block N
8. In class
Trigonometry & Vector Components
S
O
H
C
A
H
T
O
A
Trigonometry & Vector Components
S in
O pp
H yp
C os
A dj
H yp
T an
O pp
A dj
Trigonometry & Vector Components
S in
O pp
H yp
C os
A dj
H yp
T an
O pp
A dj
opp
sinΘ = hyp
adj
cosΘ = hyp
opp
tanΘ = adj
Trigonometry & Vector Components
S in
O pp
H yp
C os
A dj
H yp
T an
O pp
A dj
opposite
opp
sinΘ = hyp
adj
cosΘ = hyp
opp
tanΘ = adj
Θ
adjacent
A
Θ
cosΘ =
adj
hyp
sinΘ =
opp
hyp
tanΘ =
opp
adj
cosΘ =
Ax
A
sinΘ =
Ay
A
tanΘ =
Ay
Ax
Ax = A∙ cosΘ
Ay = A∙ sinΘ
Θ = tan-1 ( Ay
Ax
)
A
Ay
Ay
Θ
Ax
Ax2 + Ay2 = A2
cosΘ =
adj
hyp
sinΘ =
opp
hyp
tanΘ =
opp
adj
cosΘ =
Ax
A
sinΘ =
Ay
A
tanΘ =
Ay
Ax
Ax = A∙ cosΘ
Ay = A∙ sinΘ
Θ = tan-1 ( Ay
Ax
)
Ex 1) A bus travels 23 km on a straight road that is 30° north of east. What are
the north and east components if its displacement?
Ex 2) A boat travels with a speed of 20 m/s due east. The current moves at 5 m/s
due south. What is the speed if the boat w.r.t. the shore, and what angle does
it head?
Ex 1) A bus travels 23 km on a straight road that is 30° north if east. What are
the north and east components if its displacement?
dx = d ∙ cosΘ
= (23km) ∙ cos30°
=19.9km
dy
30°
dx
dy
dy = d ∙ sinΘ
= (23km) ∙ sin30°
=11.5km
Ex 2) A boat travels with a speed of 20 m/s due east. The current moves at 5 m/s
due south. What is the speed if the boat w.r.t. the shore, and what angle does
it head?
Ex 1) A bus travels 23 km on a straight road that is 300 north if east. What are
the north and east components if its displacement?
dx = d ∙ cosΘ
= (23km) ∙ cos30°
=19.9km
dy
dy
30°
dy = d ∙ sinΘ
= (23km) ∙ sin30°
=11.5km
dx
Ex 2) A boat travels with a speed of 20 m/s due east. The current moves at 5 m/s
due south. What is the speed if the boat w.r.t. the shore, and what angle does
it head?
20 m/s
Θ
v =?
v2 = 202 + 52
5 m/s
= 20.6 m/s
5
Θ = tan-1( 20 ) = 14°
HW #9. What are the components of a vector of magnitude 1.5 m at an angle
of 35° from the positive x-axis?
HW #9. What are the components of a vector of magnitude 1.5 m at an angle of
35° from the positive x-axis?
dx = d ∙ cosΘ
= 1.5m ∙ cos350
= 1.2m
dy
dy
dx
dy = d ∙ sinΘ
= 1.5m ∙ sin350
= .86m
Ch 4 HW #2
9-15
For lab 4.1:
- due tomorrow
- Ch4 HW#2 due at beginning of period
dy
Θ
}
dx
Ch4 HW#2 9 – 15
10. A hiker walks 14.7 km at an angle 35° south of east.
Find the east and north components of this walk.
11. An airplane flies at 65 m/s in the direction 149° counterclockwise from east.
What are the east and south components of the plane’s velocity?
Ch4 HW#2 9 – 15
10. A hiker walks 14.7 km at an angle 35° south of east.
Find the east and north components of this walk.
dx = d ∙ cosΘ
= (14.7km) ∙ cos35°
=
dx
dy
35°
dy = d ∙ sinΘ
= (14.7km) ∙ sin35°
=
dy
11. An airplane flies at 65 m/s in the direction 149° counterclockwise from east.
What are the east and south components of the plane’s velocity?
vx = v ∙ cosΘ
= (65m/s) ∙ cos149°
=
149°
vx
vy
vy = v ∙ sinΘ
= (65m/s) ∙ sin149°
=
12. A golf ball, hit from the tee, travels 325 m in a direction 25° south of east.
What are the east and north components of its displacement?
13. An airplane flies due south at 175 km/h with respect to the air. Wind blowing at
85 km/hr to the east wrt the ground. Plane’s speed wrt the ground?
12. A golf ball, hit from the tee, travels 325 m in a direction 25° south of east.
What are the east and north components of its displacement?
dx = d ∙ cosΘ
= (325m) ∙ cos25°
=
dx
25°
dy
dy
dy = d ∙ sinΘ
= (325m) ∙ sin25°
=
13. An airplane flies due south at 175 km/h wrt the air. Wind blowing at 85 km/hr
to the east wrt the ground. Plane’s speed wrt the ground?
v2 = 1752 + 852
Θ v =?
175km/
hr
= 194.6 km/hr
Θ = tan-1( 85 ) = 26°
175
85km/hr
14. A rowboat is paddled at 5 m/s, with respect to the water, perpendicular
to the shore of a river that flows at 4 m/s with respect to the shore.
What is the velocity (both magnitude and direction) of the boat wrt the shore?
5
4
Θ
15. An airplane has a speed of 285 km/h with respect to the air.
There is a side wind blowing at 65 km/h with respect to Earth.
What is the plane’s speed and direction with respect to the ground?
14. A rowboat is paddled at 5 m/s, with respect to the water, perpendicular
to the shore of a river that flows at 4 m/s with respect to the shore.
What is the velocity (both magnitude and direction) of the boat wrt the shore?
v = √ 42 +52
5
4
v = 6.4 m/s
Θ
Θ = tan-1(
4
5
) = 38.7°
15. An airplane has a speed of 285 km/h with respect to the air.
There is a side wind blowing at 65 km/h with respect to Earth.
What is the plane’s speed and direction with respect to the ground?
vplane
Θ
vwind
14. A rowboat is paddled at 5 m/s, with respect to the water, perpendicular
to the shore of a river that flows at 4 m/s with respect to the shore.
What is the velocity (both magnitude and direction) of the boat wrt the shore?
v = √ 42 +52
5
4
v = 6.4 m/s
Θ
Θ = tan-1(
4
5
) = 38.7°
15. An airplane has a speed of 285 km/h with respect to the air.
There is a side wind blowing at 65 km/h with respect to Earth.
What is the plane’s speed and direction with respect to the ground?
v = √ 2852 +652
vplane
v = 292 km/hr
Θ
vwind
Θ = tan-1( 65 ) = 12.8°
285
Ch3,4 Practice Problems
20. Solve: A jet flies from LA to NY, a distance of 6000km in 5.5hrs.
What is its average speed?
21. Solve: A bike travels at a constant speed of 4m/s for 5 sec.
How far does it go?
22. Set up a model: A bike accelerates from 0.0m/s to 4.0m/s in 4 sec.
What distance does it travel?
23. Set up a model: A student drops a ball from a window 3.5m above
the sidewalk. The ball accelerates at 9.8m/s2. How fast is it going
right as it hits the sidewalk?
24. Set up: you throw a ball downward from a window at a speed of 2.0m/s.
(HW)
The ball accelerates at 9.8m/s2. How fast is it going right before
it hits the ground 2.5m below?
25. You row your boat perpendicular to shore of a river that flows
at 10m/s. Your boat has a velocity of 4m/s wrt the water.
What is the velocity of the boat wrt the shore?
At what angle does it cross?
26. An airplane is traveling at 700km/hr north wrt the air, into a headwind
(HW)
blowing at 75km/hr south wrt the ground. What is the plane’s speed
wrt the ground?
27. The Mars Lander has a vertical velocity of 5.5m/s towards the surface
(HW)
of Mars. It also has a horizontal velocity of 3.5m/s due to Martian
wind. At what speed and angle does it descend?
28. The space shuttle is rising with an average velocity of 100m/s as it is
(HW)
being pushed East by upper atmospheric wind of 25m/s.
What speed and direction do viewers on ground see?
29. Hiker leaves camp, walks 4km East, then 6 km South, then 3km East,
then 5km North, then 10km West, and then 8km North.
How far is he directly from camp?
Ch3,4 Review Problems
30. Set up model: A car is traveling at 30m/s when the driver sees a chicken
crossing the road. He takes 0.8 sec to react, then steps on the brakes
and slows to a stop at 7.0m/s2. What is total distance traveled?
31. Solve: A car passes a mileage marker reading 155.5km. It travels 2.5hrs
before passing another marker. If the car had an average speed
of 88km/hr, what will the sign read?
32. You walk 30m south then 30m east. Find the magnitude and direction
of the resulting displacement.
33. A balloon rises at 15m/s, wind is blowing at 6.5m/s West.
What is velocity and direction balloon moves wrt the ground?
34. A small plane is coasting to earth at 100mph at 20° below the horizontal.
At what rate is it approaching the ground?
35. Find the x and y components of a 20km displacement vector at 60°.
(The end)
vel
(m/s)
100
90
80
70
60
50
40
30
20
10
1 2 3 4 5 6 7 8 9 10
time (sec)