Physics 20

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Physics 20 review:
Kinematics
1. Perform the following calculations and express your answer to the correct number of
significant digits:
a) 6.5cm x 85cm =
b) 1600cm ÷ 10m/s2 =
c) 30m/s x 6.5s + 0.5 x 2.0m/s2 x (6.5s)2 =
2. How long would it take to travel 650 km at a uniform speed of 85 km/h?
3. On a 300 km trip, a motorist averages 80 km/h for the first 200 km and 60 km/h for the
remainder of the trip. Calculate the average speed for the whole trip.
4. An automobile comes to a stop from 48 km/h in 4.0 s. How far did the automobile travel in
this time?
5. An object accelerates at a rate of 4.0 m/s2. After 6.0 s, the object reaches a speed of
40.0 m/s. Determine the initial speed of the object.
6. An object has an initial speed of 5.0 m/s and a uniform acceleration of 1.5 m/s2. How far
does the object travel in 20 s?
7. A car accelerates at 1.0 m/s2 and travels 98 m in 6.0 s. What was the initial speed of the car
when it started to accelerate?
8. Through what distance must a rock fall from in order to have an instantaneous speed of
40 m/s?
9. A stone is thrown vertically upward at 20 m/s. How high will it rise and how long will it
remain in the air?
10. A ball is thrown downward at 15 m/s from a window and hits the ground below 3.0 s later.
How high is the window above the ground?
11. A rally car travels 100 km/h E for 30 min, 60 km/h N for 20 min, and then 120 km/h W for
40 min. Calculate the average speed and average velocity of the car for the whole trip.
12. A pilot wishes to fly 500 km N in an aircraft with an airspeed of 300 km/h. If the wind is
blowing 90 km/h from the west. What direction must the plane be headed and how long will
the trip take?
13. A projectile is fired horizontally from the top of a cliff with an initial speed of 3.0x102 m/s
and strikes the ground 9.4 s later. How tall is the cliff? What is the projectiles range?
14. A soccer player kicked a ball on a level field with a velocity of 12.0 m/s at an angle of 30.0
to the horizontal. Calculate:
a) The time of flight
b) The ball’s range
c) Its altitude
15. How long does an electron travelling at 6.00x107 m/s take to go from the back of your
television set to the front if the distance is 0.400 m?
16. Calculate the acceleration due to gravity on a planet where a rock will reach a speed of
3.00 m/s if dropped from a height of 1.00m.
17. What is the resultant displacement produced by walking 6.0 km east, then 4.0 km south, and
then 3.0 km north?
18. If a motor boat runs at 12.0 km/h on still water, what direction must this boat be pointed to
go straight north across a river flowing east at 10.0 km/h?
19. A steel ball rolled off of a table 0.900 m high and lands on the floor 0.750 m from the edge
of the table. What was the velocity of the ball as it left the tabletop?
Dynamics
1. Calculate the unbalanced force necessary to accelerate a 4.0 kg object at a rate of 2.0 m/s2.
2. A 10 kg object is at rest when an unbalanced force of 30 N acts on it. How far will it travel
in 5.0 s?
3. A 900 g object is accelerated from rest to 20.9 m/s in 2.20 s. If the force of friction is
1.45 N, What was the applied force?
4. A 20 kg object initially at rest moves 50 m in 4.0 s. If the object accelerates uniformly, what
was the net force on the object?
5. Determine the force of gravity on a 2.0 kg bag of sugar. What will be the force of gravity on
the same bag when located on the planet Jupiter where the acceleration due to gravity is
27 m/s2?
6. Calculate the mass of an object that has a weight of 1.00 N on the surface of the Earth.
7. a) What force is necessary to lift at uniform speed a 366 g textbook?
b) A student exerts a force of 5.00 N on the textbook. Determine the acceleration of the
textbook. (remember this is a vertical problem)
c) What would be the acceleration of the text if the student exerts an upward force of
2.50 N on the textbook?
d) If the student exerts a horizontal force of 2.50 N on the textbook to slide it across his
desk. What will its acceleration be (the force of friction is 0.20 N)?
8. An 85 kg pilot is flying a helicopter. What force does the seat exert on the pilot if the
helicopter is moving:
a) Upward at a steady speed of 10.0 m/s?
b) Upward with a uniform acceleration of 10.0 m/s2
c) Downward with a uniform acceleration of 3.00 m/s2
d) Downward in free fall?
9. Find the resultant force of 25.0 N east and 15.0 N north
10. A car going north at 20.0 m/s accelerates to 30.0 m/s in 5.00 s when a net force of
2.40 x 103 N north acts on it. What is the mass of the car?
11. Calculate the acceleration of a 975 kg sled if a force of 5.50 x 103 N acts at an angle of
30.0 to the horizontal on the sled. The coefficient of friction between the sled and ground is
0.275.
12. Calculate the force of gravity between the sun (m = 2.0 x 1030 kg) and Earth at a distance of
150 million kilometres.
13. What is the gravitational field strength at a distance of 500 km from the centre of an asteroid
with a mass of 6.0 x 1015 kg?
Circular motion, Work and Energy
1. A cyclist pedals around in a circle with a radius of 15.0 m in a time of 10.0 s.
a) What is the speed of the cyclist?
b) What is the centripetal acceleration of the cyclist?
c) What centripetal force acts if the mass of the cyclist is 55.0 kg?
2. A jet engine turns at 6.00 x 104 rpm. What is the period of this motion in seconds?
3. A car with a mass of 875 kg is going around a circular track with a radius of 65.0 m. What
is the centripetal acceleration of the car if it makes 3.00 laps in 1.00 minutes?
4. Calculate the maximum speed, in km/h, a car can round an unbanked curve of radius 30.0 m
without skidding. The coefficient of friction () between the tires and the road is 0.700.
5. A 1.50 kg brick is whirled around in a horizontal circle on the end of a 2.50 m long rope
making 1 complete circle every 3.50 s.
a) Calculate the speed of the brick
b) Calculate the tension in the rope
6. What happens to the magnitude of the force car tires exert on horizontal pavement if a car
tries to turn the same corner at twice the speed? (compare centripetal force only)
7. How fast must an airplane fly in a vertical loop of 500 m radius for the pilot to feel
weightless at the top?
8. What is the mass of Saturn if it exerts a force of 1.4 x 102 N on a 600 kg satellite at a
distance of 4.0 x 108 m?
9. What is the orbital velocity of a satellite circling mars at a distance of 3.45 x 106 m from
center? (g = 4.00 N/kg)
10. The shuttle orbits the Earth at a distance of 2.30 x 105 m above the surface in a time of
90.0 minutes. How long would a satellite take to orbit 3.00 times farther from the Earth’s
centre?
11. Which of the following terms is not correctly matched with the units?
a) force
kgm/s2
b) work
MJ
c) energy
Ws
d) power
kW
e) distance
N/J
12. Doubling the velocity of an object must
a)
b)
c)
d)
double the kinetic energy
quadruple the kinetic energy
require doubling the power
require doubling the unbalanced force
13. Which of the following cannot be a vector quantity?
a)
b)
c)
d)
force
velocity
energy
displacement
14. If a person pulls a sled horizontally across the ground (Ff = 0), the work done by the person
must be
a)
b)
c)
d)
greater than the increase in the kinetic energy of the sled
less than the increase in the kinetic energy of the sled
equal to the increase in the kinetic energy of the sled
equal to the increase in the potential energy of the sled
15. A motor hoists a 75.0 kg mass 12.0 m vertically upward in a time of 8.00 s. The power of
the motor is
a)
b)
c)
d)
110W
0.720 kW
0.900 kW
1.10 kW
16. The work done pulling a 25.0 kg mass up 12.0 m along a 15.0slope is
a)
b)
c)
d)
0.300 kJ
0.762 kJ
2.90 kJ
3.00 kJ
17. Ignoring friction, calculate the power required to accelerate a 375 kg motorcycle from rest
to 72.0 km/h in 6.00 s.
18. What is the kinetic energy of an 875 kg car moving at 12.0 m/s east?
19. An orange falls from the branch of a tree that is 3.80 m above the ground. How fast is the
orange moving just before striking the ground?
20. How high can a high jumper jump if the jumper leaves the ground with kinetic energy of
1.53 kJ and has a mass of 68 kg?
Oscillatory Motion and Mechanical Waves
Workbook p. 181-185
Additional:
Unit A:
p. 11 #8 a). b).
p. 25 #3 b).
p. 43 #10
p. 46 #5
p. 48 #3, #4
Unit B:
p. 79 #3, 5
p. 86 #6
p. 90 #2
p. 92 #18
Unit C:
p. 100 #6
p. 101 #10, 11 a). b).
p. 107 #2
p. 111 #10 a). b). c).
p. 113 #5
p. 115 #2
p. 122 #4
p. 126 #5, 8
Unit D:
p. 158 #5, 7
p. 168 #2
p. 172 #3
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