Physics section 1

On an axis in which moving from right to left is positive, what is the displacement and distance of a student who walks 32 m to the right and then 17 m to the left?

• Displacement is -15 m and distance is -49 m.

• Displacement is -15 m and distance is 49 m.

• Displacement is 15 m and distance is -49 m.

• Displacement is 15 m and distance is 49 m.

Tiana jogs 1.5 km along a straight path and then turns and jogs 2.4 km in the opposite direction. She then turns back and jogs 0.7 km in the original direction. Let Tiana’s original direction be the positive direction. What are the displacement and

distance she jogged?

• Displacement is 4.6 km, and distance is -0.2 km.

• Displacement is -0.2 km, and distance is 4.6 km.

• Displacement is 4.6 km, and distance is +0.2 km.

• Displacement is +0.2 km, and distance is 4.6 km.

What does it mean when motion is described as relative?

• It means that motion of any object is described relative to the motion of Earth.

• It means that motion of any object is described relative to the motion of any other object.

• It means that motion is independent of the frame of reference.

• It means that motion depends on the frame of reference selected.

If you and a friend are standing side-by-side watching a soccer game, would you both view the motion from the same reference frame?

• Yes, we would both view the motion from the same reference point because both of us are at rest in Earth’s frame of reference.

• Yes, we would both view the motion from the same reference point because both of us are observing the motion from two points on the same straight line.

• No, we would both view the motion from different reference points because motion is viewed from two different points; the reference frames are similar but not the same.

• No, we would both view the motion from different reference points because response times may be different; so, the motion observed by both of us would be different.

What is the difference between distance and displacement?

• Distance has both magnitude and direction, while displacement has magnitude but no direction.

• Distance has magnitude but no direction, while displacement has both magnitude and direction.

• Distance has magnitude but no direction, while displacement has only direction.

• There is no difference. Both distance and displacement have magnitude and direction.

Which situation correctly identifies a race car’s distance traveled and the magnitude of displacement during a one-lap car

race?

• The perimeter of the race track is the distance, and the shortest distance between the start line and the finish line is the magnitude of displacement.

• The perimeter of the race track is the magnitude of displacement, and the shortest distance between the start and finish line is the distance.

• The perimeter of the race track is both the distance and magnitude of displacement.

• The shortest distance between the start line and the finish line is both the distance and magnitude of displacement.

Why is it important to specify a reference frame when describing motion?

• Because Earth is continuously in motion; an object at rest on Earth will be in motion when viewed from outer space.

• Because the position of a moving object can be defined only when there is a fixed reference frame.

• Because motion is a relative term; it appears differently when viewed from different reference frames.

• Because motion is always described in Earth’s frame of reference; if another frame is used, it has to be specified with

  each situation.