Download Chapter 6 Study Guide

Chapter 6 Study Guide
1. How can a skydiver benefit from air resistance?
The skydiver will benefit from air resistance because it will slow his terminal
velocity down so he can land safely.
2. How does Newton’s second law explain why it is easier to push a bicycle than to push a
car with the same acceleration?
The bicycle has a smaller mass, so a smaller force is required to give it the same
acceleration as the car.
3. Why do you have to aim above a target that you want to hit with a thrown object?
Gravity will accelerate it downward.
4. You are a passenger in a car that is moving rapidly down a straight road. As the driver
makes a sharp left turn, you are pressed against the right side of the car. Explain why this
happens.
The car changes direction, but because of inertia your body tends to continue
traveling forward. Thus, you are pressed against the right side of the car.
5. Why is the acceleration due to gravity the same for both a cannonball and a tennis ball?
There is a larger force on the larger object but it’s harder to move, there is a
smaller force on the smaller object but it’s easier to move, these two factors will
equal out and both objects will hit at the same time.
6. Definitions:
a. Newton’s First Law of Motion
An object at rest remains at rest, and an object in motion remains in motion at
constant speed and in a straight line unless acted on by an unbalanced force.
b. Newton’s Second Law of Motion
The acceleration of an object depends on its mass and the force acting on it.
c. Newton’s Third Law of Motion
All forces act in pairs. For Every action there is an equal and opposite
reaction.
d. Inertia
The tendency of all objects to resist any change in motion.
e. Free Fall
The motion of a body when only gravity acts on it
f. Terminal Velocity
The constant velocity of a falling object when the force of gravity is balanced
by air resistance.
7. Describe projectile motion and the two components that make up projectile
motion.
The curved path of a thrown object near Earth’s surface; Horizontal and
Vertical Components
a. What force causes the horizontal motion?
The force of your hand on the ball
b. What force causes the vertical motion?
The force of gravity pulling down on the ball
c. Which direction is a projectile accelerated?
Objects always accelerate downward at a rate of 9.8m/s2
8. What is the rate that all objects accelerate towards Earth?
9.8m/s2
9. Describe air resistance and the 3 factors that affect air resistance.
Air Resistance - the force that opposes the motion of objects through air
- The 3 factors are Size, Shape and Speed
10. What is the law of conservation of momentum?
The law of conservation of momentum states that when two objects collide,
their combined momentum remains the same after the collision.
11. After two objects collide, describe what happens to the momentum, mass and
velocity if they (a) stick together or (b) bounce off one another.
a. Momentum stays the same; The masses are added together; The velocity
will change
b. The momentum stays the same, but is transferred.
Acceleration:
a.
b.
c.
9.8m/s2
9.8m/s2
9.8m/s2
Challenge Yourself:
473 m/s
Force:
a. 690 N
b. 98,750 N
c. 1, 574,272 N