A woodchuck runs 25 m to the right in 7 s, then turns and runs 12 m to the left in 3 s. (Assume motion to the right is positive. Where applicable, indicate the direction with the sign of your answer. Enter your answers in m/s.) (a) What is the average velocity of the woodchuck? m/s (b) What Iis its average speed? m/s

Answer: average velocity = - 0.37m/s, average speed = 3.785m/s

Explanation: when the woodchuck moved to the right, distance covered is 25m taking 7s to cover the distance

Speed = 25/7 = 3.57m/s

Velocity = 3.57, due right (east)

When it moved to the left, distance covered is 12m and time is 3s

Speed = 12/3 = 4m/s.

Velocity = 4m/s due left (west).

a) the average velocity = 3.57 - 4 = - 0.37m/s.

This shows that the average velocity has a magnitude of 0.37m/s but in the negative direction (left). Since right represent the positive direction and left represent the negative direction.

b)

Average speed = (4 + 3.57) / 2

Average speed = 7.57/2

Average speed = 3.785m/s.

This is because speed is a scalar and independent on direction.