Modified True/False
Indicate
whether the sentence or statement is true or false. If false, change the identified word or
phrase to make the sentence or statement true.
|
|
|
1.
|
Unbalanced forces maintain motion at constant velocity.
_________________________
|
|
|
2.
|
The
property of matter that resists a change in motion is called inertia.
_________________________
|
|
|
3.
|
According to Newton’s second law of motion, force equals mass times
weight. _________________________
|
|
|
4.
|
Friction depends on the types of surfaces involved and how hard the surfaces
push together. _________________________
|
|
|
5.
|
The
force of gravity decreases as the masses of objects increase.
_________________________
|
|
|
6.
|
When
the only force acting on a falling object is air resistance, the object is said to be in free
fall. _________________________
|
|
|
7.
|
Newton’s third law of motion explains that forces act alone.
_________________________
|
|
|
8.
|
A
unit of momentum is kg•m/s. _________________________
|
|
|
9.
|
A
rocket will move upward as long as the thrust is greater than the pull of gravity.
_________________________
|
|
|
10.
|
The
force that keeps a satellite in Earth orbit is always directed away from the center of Earth.
_________________________
|
Essay
|
|
|
11.
|
In an
amusement park ride, a girl stands with her back against the inside wall of a circular room. The room
begins to whirl around. After the room reaches a constant speed, the floor drops down, but she
doesn’t fall. Identify three forces acting on her and give the direction of each. Explain which
forces are balanced forces.
|
|
|
12.
|
A
book is sitting on the dashboard of a car that is stopped at a traffic light. As the car starts to
move forward, the book slides backward off the dashboard. Use the term inertia to explain what
happened.
|
|
|
13.
|
A
block of wood is at rest on a wooden ramp. When wheels are attached to the block of wood, it moves
down the ramp. Explain each situation in terms of friction.
|
|
|
14.
|
Compare the effects of gravity and air resistance on a falling skydiver before and
after she opens her parachute.
|
|
|
15.
|
What
is the law of conservation of momentum? How can you show that the law is true for two objects that
collide?
|
|
|
16.
|
Why
don’t action-reaction forces cancel out?
|
|
|
17.
|
An
object launched from Earth must attain a speed of 7,900 m/s to achieve a low orbit. What happens if
the object’s maximum speed is less than 7,900 m/s?
|
|
|
18.
|
A
skydiver with a mass of 70 kg accelerates to Earth at a rate of 9.8 m/s2 due to gravity.
What is the force on the skydiver? Explain how you determined the answer and its units.
|