Physics Unit Exam 1

1.

1 point

28. Which of the following in NOT an example of Newton's third law of motion?

a rocket blasting off into space

sitting in a chair

a large boulder sitting on the side of the road

hitting a baseball with a bat

2.

1 point

13. Balanced forces applied to an object ___.

change the direction of the moving object

cause an object at rest to start moving

produce a negative net force

produce a net force of zero

3.

1 point

25. Newton's second law of motion states that an object's acceleration ___.

decreases as its mass increases and as the force acting on it increases

increase as its mass increases and as the force acting on it increases

decreases as its mass decreases and as the force acting on it increases

increases as its mass decreases and as the force acting on it increases

4.

1 point

14. A good rule of thumb around a swimming pool is "no running". The deck around a pool becomes slippery when wet due to ___ friction.

fluid

sliding

rolling

static

5.

1 point

2. Rolling friction ___.

is less than sliding friction

is the same as fluid friction

makes it difficult to move objects on wheels

all of these

6.

1 point

9. If a bus is traveling 15 m/s south and speeds up to 20 m/s, this is a change in ___.

acceleration

velocity

speed

all of these

7.

1 point

17. An object's velocity remains constant when its ___ do not change.

time in motion and direction

speed and direction

speed and time in motion

distance traveled and time

8.

1 point

16. In an action film, the hero is running forward along the top of a train going 40 m/s. He is chasing a villain at a rate of 3 m/s. What is the resultant velocity of the hero?

3 m/s forward

43 m/s forward

120 m/s forward

37 m/s forward

9.

1 point

29. The curved path resulting from inertia and gravity working together on a moving object is known as ___.

centripetal force

projectile motion

inertial gravitation

centripetal acceleration

10.

1 point

10. A plane passes over Cresson with a velocity of 8,000 m/s north. This same plane passes over Altoona 40s later at a velocity of 10,000 m/s. What is the plane's acceleration from Cresson to Altoona?

2,000 m/s N

50 m/s N

2,000 m/s/s N

50 m/s/s N

11.

1 point

23. If three balls were dropped from a height all at the same time, which would hit the ground first? (Assume there is no air resistance.)

they would all hit at the same time

a tennis ball

a solid rubber ball

a solid steel ball

12.

1 point

12. What is the net force when you combine a force of 7N north with a force of 5N south?

12 N south

12N north

2N north

2N south

13.

1 point

7. A reference point for determining position and motion could be ___.

a slower moving object

all of these

the Earth's surface

a building

14.

1 point

24. What force is necessary to accelerate a 1,250 kg car at a rate of 40 m/s/s?

1,250 N

40.0 N

31.25 N

50,000 N

15.

1 point

5. Which type of friction causes a sky diver's acceleration to change as she falls?

all of these

rolling

sliding

fluid

16.

1 point

20. When a soccer ball is kicked, the action and reaction forces do not cancel each other out because ___.

the forces act at different times

the force of the foot on the ball is larger than the force of the ball on the foot

all of these

the forces act on two different objects in different directions

17.

1 point

3. If Earth's mass doubled, your weight would ___.

decreases because gravity increases

increase because gravity increases

decreases because gravity decreases

increases because gravity decreases

18.

1 point

22. Acceleration of an object ___.

decreases as the mass of the object increases

increases as the force on the object increases

is in the same direction as the force on the object

all of these

19.

1 point

26. Newton's third law of motion states that if a force is exerted on an object. another force occurs that is ___.

is in the same direction and speed

equal in size and opposite in direction

is equal in speed and opposite in direction

is in the same direction and size

20.

1 point

21. Newton's first law applies to ___.

objects that are not moving

objects that are accelerating

objects that are moving

both a and c

21.

1 point

15. Gravitational forces depend on ___ and ___.

mass and velocity

distance and speed

direction and mass

distance and mass

22.

1 point

30. Which of the following will have the greatest air resistance?

a flat 8" x 11 piece of paper

an acorn

an apple

a crumpled up piece of paper

23.

1 point

27. Staying seated in a chair is an example of Newton's ___ law(s).

second and third

first and fourth

second

first and third

24.

1 point

8. In 1.5 hours you walk 7.5 km. When you divide 7.5 by 1.5 you are calculating ___.

instantaneous speed

force

acceleration

speed

25.

1 point

1. Friction is a force that ___.

increases with a larger mass

decreases when surfaces are smooth

all of these

opposes an object's motion

26.

1 point

6. The force of gravity is greater between two objects that ___.

are farther apart

have greater masses

have rougher surfaces

are moving at greater speeds

27.

1 point

18. At the bottom of a hill a runner jobs 4 m/s north. One minute later, at the top of the hill, the jogger's velocity is 1 m/s north. What is the jogger's acceleration from the bottom of the hill to the top?

3 m/s/s north

-3 m/s/s north

0.05 m/s/s north

-0.05 m/s/s north

28.

1 point

19. You ride your bike around a corner at a constant velocity of 11 km/hr. What changes?

your velocity

your acceleration

none of these

both a and b

29.

1 point

11. An example of acceleration is ___.

bicycling at 4 m/s

a hovering helicopter

a car turning a corner

all of these

30.

1 point

4. A force ___.

is a push or pull

is expressed in Newtons

all of these

can cause an object to speed up, slow down, or turn