Intro to Physics
Midterm Review & Study Guide
Mrs. DiOrio & Mr. Dougherty
Unit 1
Try these conversions, using the ladder method.
1000 mg = ____1___ g
1 L = _____1000__ mL
160 cm = ___1600____ mm
14 km = ___14000____ m
3
109 g = ____.109___ kg
250 m = ____.250___ km
Compare using <, >, or =.
56 cm ___<___
6m
7 g __>____ 698 mg
Unit 2
1. What is speed? Speed = Distance/Time
2. If you are traveling around the Somerville circle at 25 mph what stays constant?
Speed
3. When you are graphing, what variable goes on the x-axis?
Time
4. What tool do you use to measure instantaneous speed?
a. speedometer
b. tape measure
c. stop watch d. odometer
5. What tool do you use to measure how far your trip was?
a. speedometer
b. scale
c. stop watch d. odometer
7. Name 3 units of speed.
a. __________________________Miles per hour
b. __________________________Meters per second
c. __________________________Inches per hour
8. What is the formula for acceleration?
Change in velocity / Change in time
9. Define independent and dependent variable.
Independent is manipulated by the researcher, the dependent is what comes
out.
10. Two cars are traveling in opposite directions going 60 mph. Do they have the
same velocities?
No, velocity is a speed and a direction.
11. What is the formula for speed?
Speed = Distance * Time
12. What is the formula for distance?
Distance = Speed / Time
13. See # 11 & know the formula for speed. Thank you.
14. What does a speedometer in a car tell you?
Instantaneous Speed
15. What is acceleration?
Rate of change of velocity
16. What is the difference between speed and velocity?
Velocity has a specific direction.
17. What is the formula for acceleration?
Change in acceleration / change in time
18. What is free fall?
A fall where only the weight of the object is present.
19. A ball is thrown upwards and caught when it comes
back down. In the absence of air resistance, the speed of
the ball when caught would be; the same as, faster than,
or less than when thrown upwards?
20. An object is in free fall. For each second the object is
falling, what happens to its speed?
It increases
21. If you drop a feather and a coin at the same time in a
tube filled with air, which one will reach the bottom of
the tube first? Why?
Coin, feather will hit resistance.
22. Please see #13. Know the formula for speed. Thank
you.
23. Please see #22. Know the formula for speed. Thank
you.
24. What is the value for gravity on the Earth’s surface?
9.8 : a
25. Which unit is more accurate? The centimeter or the millimeter?
Millimeter
26. What is the correct order of metrics going from the largest to the smallest?
KHD B DCM
27. 1000 mg = ________1_____ g
28. 160 cm = _______1600_______ mm
29.
109 g = _______.109_______ kg
30. Determine the percentage error in: Experimental Value 135.2, Accepted Value
133.4.
Accepted Value – Experimental Value * 100
Accepted Value
1.35%
31. Please see # 23. Know the formula for speed. Thank you.
32. What are the SI base units for:
Distance: Meter
Mass: Gram
Time: Seconds
Unit 3 Newton’s Laws
1. What does Newton’s 1st Law say?
An object at rest will stay at rest, and object in motion will stay in
motion.
2. What is a force?
A push.
3. Define: Inertia
The tendency of an object to resist change wheter it is in motion or
motionless.
4. Name 4 types of friction.
1. Sliding
2. Rolling
3. Fluid
4. Static
5. What does Newton’s 2nd Law say?
The net force is equal to the acceleration placed on the mass.
6. What is the formula for Force?
F=M*A
7. What is the unit of measure for force?
N
8. What is the difference between mass and weight?
Mass is the amount of matter an object has while weight is a
measure against gravity.
9. What is the formula for Weight?
W=M*A
10. How is gravity represented and what is it’s value?
A, 9.8
11. What does Newton’s 3rd Law say?
For every action on an object there is an equal and opposite
reaction.
12. Describe how a fish moves through water using Newton’s 3rd Law.
The force against the water from its fins is using the reactive force
from the water to move forward.
Thinking Questions:
13. Suppose you stand on a scale in the weight room and the scale
reads 110N. Now, if you were to stand on two scales next to each
other at the same time, what would each scale say?
55N
14. How does mass effect acceleration?
The more mass an object has the more acceleration it will need to
move.
15. Mrs. DiOrio is pushing a box in one direction with 200 N of force.
Mr. Dougherty is pushing on a box in the opposite direction with 200
N of force. Which way is the box going and why?
Nowhere, the forces acting on it are the same each way.
16. What causes a moving object to change direction?
Acceleration
17. A bus is cruising along a dark desert highway when all of the
sudden a bug splatters across the windshield. Which force is greater,
the bus hitting the firefly or the firefly hitting the bus?
It’s the same.
18. If the force on an object is doubled, the acceleration will change by
how much?
2x
19. How does a rocket move through space?
It brings its own oxygen supply and the fuel burns, producing a
disaplcement of gas that pushes it forward.
20. What is the reaction force of a ball dropping from the air?
The bounce
Mathematic Section
21. If a woman has a mass of 50 kg, calculate her weight in Newtons.
50 * 9.8 = 490 N
22. Susie Smart weighs 300N. Calculate her mass.
300 / 9.8 =30.61
23. What is the weight of 2 kilograms of yogurt in Newtons?
2 * 9.8 = 19.6
24. A little boy who weighs 40 kg is riding in a wagon pulled by a
horse. What is the acceleration of the wagon if the horse pulls with a
force of 30 N?
30 / 40 = .75
25. A racecar breaks down. It weighs 700 kg. The driver can push with
an acceleration of .05 m/s2. How much force is he putting on the car?
700 * .05 = 35 N
26. A 1500kg car accelerates at a rate of 4.0 m/s2. How much force is
the car’s engine producing?
1500 * 4.0 = 6000 N
27. A golf ball, weighing .34 kg is accelerated at a rate of 174 m/s2.
What force does the golfer’s club put in the ball?
.34 * 174 = 59.16
28. A bottle of Gatorade weighing 1.4 kg is tossed to you at a rate of 14
m/s2. You miss it and it hits you with how much force?
1.4 * 14 = 19.6
29. A woman is pushing a shopping cart with 18 N of force. The cart
weighs 28 kg. What is her acceleration?
18 / 28 = .64
30. A speedboat pulls 2 water skiers, each with a mass of 55 kg. What
is the total weight of the water-skiers in Newtons?
110 * 9.8 = 1078
Cumulative Review Questions
31. 1000mg = _______1_____ g
32. Determine the percent error of Accepted Value: 134.2 and
Experimental Value 165.9.
23%
33. How do you define acceleration?
Rate of change of speed / time
34. When measuring, which ruler is more accurate, the centimeter or
the millimeter?
mm
35. 109 g = ____.109________ kg
Momentum
1. What are the two variables that momentum depends on?
Mass & velocity
2. Momentum can be defined as
The quantity of motion of an object, mass in motion.
3. Which of the following is the correct symbol for momentum?
a. M
b. Mom
c. P
d. F
4. List the units for each variable:
P=
kg * ms^2
M=
kg
V= ms^2
5. The momentum of an object at rest is _________0___________ .
6. Which has a greater amount of momentum, a mack truck going 40 m/s2 or a
skateboarder going 40 m/s2?
Mack truck, because it has more mass.
7. To stop an object, we have to apply a force over a period of ____time_____________ .
8. What is the formula for impulse?
Impulse = Force * Change in time
9. What are the units for impulse?
N*S
10. The greater the time over which the collision occurs, the smaller the
___________force____ acting on the object.
11. In order to minimize the effect of the force on an object involved in a collision,
what can you do?
Increase the time
12. What does the law of conservation of momentum state?
No net external force acting on a system = Momentum before = momentum
after
13. Describe the kinetic energy in an elastic collision. Give an example of an elastic
collision.
Kinetic energy is conserved KE before = KE after, crazy ball bouncing,
electrons scattering.
14. Describe the kinetic energy in an inelastic collision. Give an example of an elastic
collision.
Kinetic energy is NOT conserved KE before does not = KE after.
Catching a baseball, football tackle, cars colliding
15. Choose whether each collision in elastic or inelastic.
I = Inelastic
____I____
raquet)
E = Elastic
A tennis player returning a serve. (Specifically, the ball on
_____I___
A truck crashing into a bridge.
_____I___
An egg falling and cracking on the ground.
_____E___
Billiards balls colliding.
16. A 185.25 kilogram motorcycle is moving at a speed of 87.75 m/s. What is the
momentum of the cycle?
185.25 * 87.75 = 16255.69
17. If the motorcycle above crashes into a wall and stops in a time of 0.05 seconds,
how much force acted on the cycle to bring it to a stop?
16255.69 * .05 = 812.78
18. Calculate the momentum of a 1200 kg car with a velocity of 25m/s.
1200 * 25 = 30,000
19. What is the momentum of a child and wagon if the total mass of the
child and wagon is 22kg and the velocity is 1.5m/s?
22 * 1.5 = 33
20. The parking brake on a 1200kg automobile has broken, and the vehicle has
reached a momentum of 7800kg.m/s. What is the velocity of the vehicle?
7800 / 1200 = 6.5
21. A roller coaster climbs up a hill at 5 m/s2 and then zips down the hill at 40 m/s2.
When is momentum greater: going up the hill or going down the hill?
Downhill
22. A soccer ball crashes into another soccer ball at rest. Does the total momentum
of the balls increase, decrease or stay the same?
Stays the same
23. What would you need to do to increase the momentum of a golf ball?
Hit it harder, increase mass of golf ball
24. Why are dashboards padded in cars?
To increase the time over which the impact occurs, lessen force
25. A freight train rolls down the track. If it were to keep rolling at the same speed,
but had twice as much mass, its momentum would be __________2x___________________.
26. What is the momentum of a 10 kg bowling ball at 2 m/s2?
10 * 2 = 20
27. What impulse occurs when an average force of 13 N is exerted on a cart for 4
seconds?
13 * 4 = 52 N*S
28. What is the momentum of a 60 kg carton that slides at 4 m/s across an icy
surface?
60 * 4 = 240 kg*m/s
29. How much momentum does a 3000 kg truck have traveling at 25 m/s?
3000 * 25 =75000
30. A halfback (m = 60 kg), a tight end (m = 90 kg), and a lineman (m = 120 kg) are
running down the football field. Consider their ticker tape patterns below.
Compare the velocities of these three players. How many times greater are
the velocity of the halfback and the velocity of the tight end than the velocity
of the lineman?
Which player has the greatest momentum? Explain.
Lineman = 120 * 3 = 360
Tight End = 90 * 6 = 540
Halfback = 60 * 9 = 540