The college physics department attached motion sensors to a football halfback. A
ID: 3308972 • Letter: T
Question
The college physics department attached motion sensors to a football halfback. At one instant during the big game, the sensors indicated that the halfback's instantaneous motion was -25 m/s,and +9 m/s. Which of the following statements best describe his motion at this instant? Note: The halfback wants to 'gain yardage, which means his goal is to move in the positive (+) direction. Elimination Tool A He is gaining yardage while losing speed quickly (experiencing more than 1'g'). B He is losing yardage while losing speed at a moderate rate (experiencing less than 1'g) C He is gaining yardage while losing speed at a moderate rate (experiencing less than 1 'g). D He is gaining yardage, while gaining speed quickly (experiencing more than 1'g')Explanation / Answer
Yes, answer A is the correct one. The velocity is +9 m/s, which means he is moving in the positive direction (gaining yardage). However, his acceleration is negative, which means he is losing speed and he is losing it very quickly (more than 1 g, since 1 g is just 10 m/s^2). So the answer A is correct.