Determine whether the object is speeding up or slowing down. (questions in description).

Question

Determine whether the object is speeding up or slowing down.

12. The velocity is positive and the acceleration is positive.

13. The velocity is negative and the acceleration is positive.

         

14. The velocity is positive and the acceleration is negative.

15. The velocity is negative and the acceleration is negative.

16. The velocity is zero and the acceleration is positive.

Answer 1

Velocity and acceleration are both vectors. Let's assume positive direction to the right.

So for 12. object moving to the right (positive speed) and accelerating to the right (so speed must be increasing , direction not changing). So speeding up

For 13. Object moving to left (as velocity negative). Accelerating to the right (as positive acceleration). So speed to the left must be reducing as change of velocity is to the right. So slowing down

For 14. Moving to the right, acceleration to the left, so slowing down (same situation as 13 but directions reversed)

For 15. Speeding up (same situation as 12, directions reversed)

For 16. Speeding up. (initial speed 0).

Mike

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