Study Guide for the Chapter 11 and Gravity Test
Maine Learning Results
D4a Describe the contribution of Newton to our understanding of force and motion, and give
examples of and apply Newton’s three laws of motion and his theory of gravitation.
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D1b Explain the role of gravity in forming and maintaining planets, stars, and the solar system.
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Section 1
1. Identify the law that says that objects change their motion only when a net force is
applied.
2. Relate the first law of motion to important applications, such as seat-belt safety issues.
3. Calculate force, mass, and acceleration by using Newton’s second law.
Section 2
1. Explain that gravitational force becomes stronger as the masses increase and rapidly
becomes weaker as the distance between the masses increases.
2. Evaluate the concept that free-fall acceleration near Earth’s surface is independent of the
mass of the falling object.
3. Demonstrate mathematically how free-fall acceleration relates to weight.
4. Describe orbital motion as a combination of two motions.
Section 3
1. Explain that when one object exerts a force on a second object, the second object exerts a
force equal in size and opposite in direction on the first object.
2. Show that all forces come in pairs commonly called action and reaction pairs.
3. Recognize that all moving objects have momentum.
4. State and apply the law of conservation of momentum.
Vocabulary
Force
Mass
Weight
Free Fall
Momentum
Inertia
Newton’s First Law
Newton’s Second Law
Equations:
Newton’s Law of Universal Gravitation
Universal Gravitational Constant
Law of Conservation of Momentum
Terminal Velocity
Projectile Motion
Newton’s Third Law
Acceleration
Velocity
Sample Questions and Problems
1. Calculate the acceleration of a 82 kg couch that is pushed across the floor with an
unbalanced force of 21 N.
2. Explain why a backward-facing car seat is safer for an infant than a seat that faces
forward during a collision or abrupt stop.
3. Identify which pair of objects would have greater gravitational force between them in the
examples below. Use the law of universal gravitation to explain your answers.
4. Calculate the mass in kg of an object that weighs 1225 N on Earth.
5. Use Newton’s Law of Universal Gravitation to find the force of gravity between two
objects that are 2 meters apart. One has a mass of 10 kg and the other has a mass of
125,000 kg.
6. Apply Newton’s third law of motion to explain how two billiard balls moving toward
each other at the same speed collide and move away from each other at the same speed as
before.
7. Apply the concept of momentum to compare the mass and velocity of a slow- moving
train and of a high-speed bullet.
8. Indicate which of the following has greater momentum: a 500 kg car moving at 64 kin/h,
a 250 kg cart moving at 128 km/h, or a 1000 kg truck moving at 32 km/h. Justify your
answer.
9. Explain the difference between weightless and free fall.
10. Two children are skating. One child has a mass of 50 kg and is skating at a velocity of 5
m/s to the east. Her younger sister has a mass of 25 kg and is standing still. The older
sister collides with her little sister and hangs on to her as they glide together. At what
velocity will the pair move after the collision?
11. What is the difference between mass and weight?