Science Bowl Practice Questions

Physics - 2

8.

Multiple Choice: The work done by a friction force is:

w) always positive
x) always negative
y) always zero
z) either positive or negative depending upon the situation.

ANSWER: X -- ALWAYS NEGATIVE

9.

Multiple Choice: As defined in physics, work is:

w) a scalar quantity
x) always a positive quantity
y) a vector quantity
z) always zero

ANSWER: W -- A SCALAR QUANTITY

10.

Multiple Choice: A pendulum which is suspended from the ceiling of a railroad car is observed to hang
at an angle of 10 degrees to the right of vertical. Which of the following answers could explain this
phenomena?

w) The railroad car is at rest.
x) The railroad car is accelerating to the left.
y) The railroad car is moving with constant velocity to the right.
z) The railroad car is accelerating to the right.

ANSWER: X -- THE RAILROAD CAR IS ACCELERATING TO THE LEFT.

11.

Multiple Choice: Two forces have magnitudes of 11 newtons and 5 newtons. The magnitude of their
sum could NOT be equal to which of the following values?

w) 16 newtons
x) 5 newtons
y) 9 newtons
z) 7 newtons

ANSWER: X -- 5 NEWTONS

12.

Short Answer: A ball leaves a girl's hand with an upward velocity of 6 meters per second. What is the
maximum height of the ball above the girl's hand?

ANSWER: 1.8 METERS

13.

Short Answer: A boy throws a ball vertically upward with a velocity of 6 meters per second. How long
does it take the ball to return to the boy's hand?

ANSWER: 1.22 SECONDS (accept: 1.2 seconds)

14.

Short Answer: A toy train moves in a circle of 8 meters radius with a speed of 4 meters per second.
What is the magnitude of the acceleration of the train?

ANSWER: 2 METERS PER SECOND SQUARED

15.

Short Answer: A certain machine exerts a force of 200 newtons on a box whose mass is 30 kilograms.
The machine moves the box a distance of 20 meters along a horizontal floor. What amount of work
does the machine do on the box?

ANSWER: 4000 JOULES