Download Newton`s Laws and Gravity Review

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Intro Physics: Newton’s Laws and Gravity Review
Mass, Weight, and Gravity
1. According to Newton’s Law of Universal Gravitation, every object that has mass
exerts a gravitational force of attraction on every other object that has mass.
a. What object exerts the strongest force of gravity on you?
b. Why is its force of gravity on you stronger than the force of gravity that your friend
exerts on you even though you are equally close to both of them?
c. Why is its force of gravity on you more important than the force of gravity that the
Sun exerts on you even though the sun has much, much more mass?
2. Your little sister tells you that mass and weight are the same. You know better!
Please explain, in words that your little sister understands, what the difference
between mass and weight is.
Standard(s): 1.4, 1.7
TA: _____________
Independence Level: __________%
Assistance, coaching, prompting: __________________________________________________
3. There are 4 identical hands that are at different distances from the sun. Which hand
has the largest force of gravitational attraction to the sun? Why does it have the
largest force?
   
SUN
B
A
C
D
4. There are 4 phones around the sun. All 4 phones are the same distance from the
center of the sun, but they have different masses. Which phone has the largest force
of gravitational attraction to the sun? Why does it have the largest force?
B
A
SUN
D
C
5. Which has more mass: (circle your choice)
a. a baseball
b. a bowling ball
6. Our moon has a very large mass, so it has a very large inertia and wants to move in a
straight line. Which force causes the moon to move in a fairly circular path around
the earth?
7. How many Newtons does a 5.2 kg rock weigh on the Earth?
Hint: use the formula weight = mg
8. If the 5.2 kg rock were brought to the moon, it would have a mass of _________.
(circle your choice)
a. more than 5.2 kg
b. less than 5.2 kg
c. 5.2 kg
9. A toy ball weighs 4 N on the Earth. If the toy ball were taken to the moon, it would
weigh (circle your choice)
a. more than 4 N
b. less than 4 N
c. 4 N
d. 0 N
Newton’s First Law
10. Which has more inertia: (circle your choice)
a. a baseball
b. a bowling ball
11. Auntie Kim is pulling her nephew Michael in a wagon so that he moves at a constant
speed of 1.5 m/s. When she stops applying a force the wagon, he and the wagon
quickly come to a stop. Since Michael and the wagon have mass, they have inertia
and should want to keep moving at a constant velocity (constant speed in a straight
line). Why do the wagon and Michael slow down and stop when she stops pulling?
12. One cold January morning, Freddy walks out to his car and finds it is covered in
snow. He is late for work, so he only clears the snow off of the windows and sides of
the car, leaving a big pile of snow on top of the car. Freddy pulls out of his driveway
and begins driving down the road. A few minutes later, Freddy is moving at 35 mph
when he sees his friend Madison walking down the sidewalk. He slams his foot on the
brake to stop. When he does this, the snow from the top of the car falls onto his
windshield! Why did this happen? Use Newton’s 1st Law in your explanation.
13. Without seatbelts, people could go flying through the windshield of a car that is
stopped suddenly in an accident. In terms of forces and one or more of Newton’s
laws, what are the seatbelts doing?
14. During the Inertia Smorgasbord Lab, a marble was rolled so it traveled inside a plate
that has a piece cut out. Draw the path the marble takes when it leaves the plate.
Newton’s 2nd Law
15. A motorcycle has a mass of 400 kg and accelerates at 2.5 m/s2. What is the
magnitude (size) of the net force acting on the car?
16. Kevin is pushing a cart to the left with a force of 27 N. The force of friction on the cart
is 25 N.
a. What is the net force on the cart? Be sure to include the size of the force (which is
the magnitude) and the direction of the net force.
b. Use the net force determined in PART A to determine the cart’s acceleration if the
cart has a mass of 15 kg. SHOW YOUR WORK and be sure to include the size of
the force (which is the magnitude) and the direction of the net force in your
answer!
17. What is the net force on a toy car that is moving at a constant 2 m/s in a straight line
to the left?
18. A car is pulling away from a stop sign and speeding up to the right. Circle the true
statement:
a. There is 0 N of net force acting on the car.
b. There is a net force acting on the car. The net force is directed to the left.
c. There is a net force acting on the car. The net force is directed to the right.
Newton’s 3rd Law
19. A softball player swings the bat and strikes a ball. According to Newton’s third law of
motion, which of the following is a reaction to the bat pushing on the ball? (circle your
choice)
a. the ball pushing on the bat
b. the bat pushing on the player
c. the player pushing on the bat
d. the ball pushing on the player
MCAS Questions about Force, Newton’s Laws, and Gravity
1. The force of gravity on an object depends primarily on the object’s
A. density.
B. mass.
C. momentum.
D. volume.
2. Two forces act on the 2 kg box shown below.
A 4 N force acts to the right and a 6 N force acts to the left. What is the net force acting on the
box?
A. 10 N to the right
B. 10 N to the left
C. 2 N to the right
D. 2 N to the left
3. A 1500 kg car increases its speed by 2 m/s for each second of travel. What is the net force
acting on the car?
A. 750 N
B. 1500 N
C. 3000 N
D. 6000 N
4. The tendency of a stationary object to resist being put into motion is known as
A. acceleration.
B. inertia.
C. weight.
D. velocity.
5. The illustration below shows a 2-ton elephant balancing on a tree stump.
Which of the following statements must be accurate?
A. The weight of the tree stump is greater than 2 tons.
B. A 4-ton force on the ground spreads out in all directions.
C. The tree stump is exerting a 2-ton force upward on the elephant.
D. The downward force on the ground under the tree stump is 4 tons.
6. A hot air balloon exerts a force of 1200 N while lifting a load of 800 N. Which free-body force
diagram depicts the forces involved?
7. The forces acting on a skateboarder moving at a constant velocity along a sidewalk are shown
in the figure below.
Which of the following is the net force on the skateboarder?
A. 0 N
B. 70 N
C. 670 N
D. 1270 N
8. An upward force of 150 N is applied to a box weighing 70 N. Which of the following is the
free-body force diagram for this situation?
9. Which of the following must be included with magnitude to represent a vector?
A. mass
B. direction
C. acceleration
D. volume
10. The pull of gravity on Earth is a direct result of the
A. mass of Earth.
B. magnetic field of Earth.
C. rotation of Earth on its axis.
D. weight of Earth’s atmosphere.
11. The Sun’s gravitational attraction causes a comet’s path to curve as shown in the illustration
below.
Which of the following statements best explains the fact that the Sun does not appear to move due
to the comet’s gravitational attraction?
A. The Sun’s mass is much greater than the comet’s mass.
B. The comet is too far away for its gravity to affect the Sun.
C. In this gravitational interaction only the comet exerts a pull on the Sun.
D. The path of the comet reduces the Sun’s gravity
12. The surface gravity of Pluto is the weakest of the nine planets because Pluto
A. has the lowest temperature.
B. has the smallest mass. *
C. rotates the slowest.
D. is farthest from the Sun.
13. On Earth, Johanna weighs 100 lbs. She calculated what her weight would be at several
other locations in the solar system. The results are shown in the table below
Location in
Solar System
Weight
(lbs.)
Venus
Earth
Moon
90
100
16
Mars
40
Jupiter
260
Which of the following statements is best supported by the information in the table?
A. Venus has more gravitational force than Earth.
B. Mars has less gravitational force than the Moon.
C. Earth has four times the gravitational force of Mars.
D. Jupiter has more than twice the gravitational force of Earth.
14. The Moon orbits Earth at a speed of approximately one kilometer per second. The Moon is
kept in orbit by which of the following?
A. gravity
B. lunar phases
C. magnetism
D. ocean tides