TEST on Forces

The graph shows the v-t graph of a car traveling on a rough road. The mass of the car is 1000 kg. What is the net force on the car?

• 2500 N

• 2750 N

• 3000 N

• 3250 N

A 1000-kg car is accelerating at 2.5 m/s². If the engines exert 3000 N of thrust, what is the friction force (in newtons) on the car? Express the answer in a whole number. No need to write the unit.

You push a 10-kg table in the cafeteria with a horizontal force of 25 N, and it accelerates at 0.50 m/s². What is the coefficient of kinetic friction?

• 0.20

• 2

• 0.50

• 0.25

The graph shows the velocity of the car moving in a straight line. Over which segments is the car in equilibrium? Select all that apply.

• A

• B

• C

• D

• E

A student hangs a fish on a spring scale inside the elevator. When the elevator is not moving as in Figure 1, the scale reads 50 N. When the elevator is moving as in Figure 2, the scale reads 35 N. What is the true weight of the fish?

• 50 N

• 5 kg

• 35 N

• 3.5 kg

A student hangs a fish on a spring scale inside the elevator. When the elevator is not moving as in Figure 1, the scale reads 50 N. When the elevator is moving as in Figure 2, the scale reads 35 N. What is the apparent weight of the fish when the elevator is moving?

• 50 N

• 5 kg

• 35 N

• 3.5 kg

A student hangs a fish on a spring scale inside the elevator. When the elevator is not moving as in Figure 1, the scale reads 50 N. When the elevator is moving as in Figure 2, the scale reads 35 N. What is the acceleration when the elevator is moving?

• 3 m/s², upward

• 3 m/s², downward

• 4.3 m/s², upward

• 4.3 m/s², downward

A net force of 9.0 newtons accelerates a wagon at 3.0 m/s². What net force would be required to accelerate the same wagon at 6.0 m/s²?

• 18 N

• 4.5 N

• 27 N

• 54 N

The diagram shows the forces acting on a box. If the box is 2 kg, what is its acceleration?

• 4 m/s², left

• 6 m/s², right

• 4 m/s², right

• 6 m/s², left

The diagram above shows the friction force versus the normal force acting on a wooden box that is moving at constant speed on a table. What is the coefficient of kinetic friction between the box and the table? Express the answer in two decimal places.