HOBET Science Reading Practice

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When something, a particle for instance, is moving in a straight line, its motion can be described as either positive or negative. That is, if it moves 'forward,' we can say it has accomplished positive motion, while if it moves the opposite way we will express the movement as negative. When a particle is moving in three-dimensional space, however, it is no longer possible to describe it so simply. Instead, we need to be able to describe both its magnitude and direction: something that is described in this way is known as a vector. Some of the most common vectors in physics measure displacement, velocity, acceleration, force, and magnetic field. Some physical quantities do not have a specific direction; they are known as scalars. Common scalars include temperature, pressure, energy, mass, and time. Probably the simplest vector of all is the displacement vector. A displacement, in physics, is simply a change in position. If, for instance, a particle were to move from point A to point B, a physicist would say that it has undergone displacement from A to B. In a diagram, this displacement would be shown with an arrow from point A to B; it is important that this arrow is drawn with a hollow head, so that it may be distinguished from other arrows used in physical notation. It should also be noted that the arrow of a displacement vector is not an indication of the path taken from point A to B. Instead, a displacement vector is just a summary of the overall effect of the motion, and objects could take any number of courses to arrive at this same displacement.

1. What kind of motion can be described simply as either positive or negative?
A: rotation
B: motion in a straight line
C: zigzag motion
D: motion in a circle

2. If forward motion is described as negative, what would backward motion be?
A: positive
B: negative
C: even
D: odd

3. What is the name for physical quantities that do not have a specific direction?
A: quanta
B: non-direction
C: scalar
D: vector

4. What is another word for displacement?
A: position
B: movement
C: vector
D: scalar

5. What is another name for a physical quantity that has magnitude and direction?
A: vector
B: scalar
C: radial
D: temperature

6. What is considered to be the simplest vector?
A: displacement vector
B: time
C: acceleration
D: temperature

7. Does a displacement arrow indicate the exact path of an object?
A: Yes, the arrow indicates a precise path.
B: No, the arrow is unrelated to the change in position.
C: No, the object could take any number of paths to get from A to B.
D: Yes, and the head of the arrow should be filled in.

8. What is unique about the arrow used to indicate displacement?
A: it has a dark head
B: it is made with a dotted line
C: it is curved
D: it has a hollow head

9. Which of the following is NOT a common vector?
A: velocity
B: temperature
C: acceleration
D: force

10. Which of the following is a common scalar?
A: acceleration
B: magnetic field
C: displacement
D: time

Answer Key

1. B. Only motion in a straight line can be described as either positive or negative.

2. A. Forward and backward motion are opposite, as are positive and negative.

3. C. Scalars have a magnitude but not a specific direction.

4. B. Displacement and movement both refer to changes in position.

5. A. Vectors are physical magnitudes that contain both a magnitude and a direction.

6. A. Displacement is simply a change of position.

7. C. A displacement arrow indicates a change of position, not the precise path.

8. D. The arrow used to indicate displacement has a hollow head to distinguish it from other arrows used in notation.

9. B. Temperature does not have a specific direction.