Question

a. The figure given below shows the first three points of a motion diagram. Is the object’s average speed between points 1 and 2 greater than, less than, or equal to its average speed between points 0 and 1? Explain how you can tell.

b. Use Tactics Box 1.3 to find the average acceleration vector at point 1. Draw the completed motion diagram, showing the velocity vectors and acceleration vector

Short answer

a) The average speed between points 1 and 2 is less than its average speed between points 0 and 1.

b) The average acceleration vector at point 1 is downwards.

Step-by-step solution

Step 1. Write the given information

The three dots represent the body in different positions with respect to time. The green arrows show the direction of the velocity of the body.

(a) To determine the average speed between points 1 and 2.

The distance between dots 1 and 2 is less than as compared to the distance between dots 0 and 1. This implies that the distance traveled by the body from points 0 to 1 is greater than points 1 to 2.

Therefore, the average speed of the body from points 0 to 1 is greater than the average speed between points 1 to 2.

(b) To determine the average acceleration at point 1

The average acceleration of the body is given by the change in the velocity with respect to time.

At point 1, the acceleration is determined by taking the difference between the final velocity and the initial velocity as shown below.
The average acceleration at point 1 is upwards as shown in the figure.