Forces and Motion

A bus traveled 280 kilometers between two cities. It left the first city at 3:00 p.m. and arrived at the second city at 7:00 p.m. What was the average speed of the bus during the trip?

• 4 km/h

• 40 km/h

• 70 km/h

• 280 km/h

The graph below shows a runner's distance from the starting line during a 30 minute race. Distance was measured in meters (m). Time was measured in minutes (min).

During which time interval was the object moving with the greatest average speed?

• 0 to 5 minutes

• 10 to 15 minutes

• 15 to 20 minutes

• 25 to 30 minutes

Two rescuers carry a stretcher that holds a an injured man. The total mass of the stretcher and the man is 175 kg. The man's forward acceleration is 2 m/s². What is the force necessary to produce this acceleration as the rescuers transport the man to the ambulance?

• 350 N

• 87.5 N

• 0.011 N

• 177 N

When an object has a net force that is GREATER than 0 Newtons, the object is...

• balanced and still

• balanced and moving at a constant speed

• unbalanced and accelerating

• unbalanced and still

A student applied a force of 200 N to push a box 15 m down the sidewalk. Given the formula, W=F×d

, how much work has been done?

• 30 J

• 300 J

• 3,000 J

• 30,000 J

Which of these statements best describes what will happen if the forces are applied at exactly the same time?

• The refrigerator will move left because of the greatest force on the right.

• The refrigerator will move right because the force is over a greater surface area.

• The refrigerator will remain in place because the forces are not enough to move a refrigerator.

• The refrigerator will remain in the same place because the net force is zero.

To complete a project, 200,000 Joules of work are needed. The time taken to complete the project is 20 seconds. How much power is needed?

P=W÷t

• 0.0001 J/s

• 10,000 J/s

• 200,020 J/s

• 1,000,000 J/s

An investigation is performed to determine how the angle of a ramp affects the speed of a ball as it rolls down the ramp. In addition to using the same ball and the same ramp, which of these should also remain constant?

• releasing the ball from the same position in each trial

• keeping the ramp at the same height for all trials

• keeping the ramp facing the same direction for all trials

• measuring the length of the ramp before each trial

A 20 N object is placed on a surface and starts to slide. What is the most likely reason the object begins to move?

• Gravity exerts a balanced force on the object.

• An unbalanced force causes acceleration.

• Friction is applied to the object.

• The forces acting on the object are in equilibrium.

The difference between mass and weight is that-

• weight is a measure of gravity’s effect on an object; mass is a measure of the amount of matter in an object

• weight is a measure of the amount of matter in an object; mass is a measure of gravity’s effect on an object

• weight is a measure of force; mass is a measure of velocity.

• there is no difference.