What is the relationship between the speed of an object and its kinetic energy?

For the purposes of your question, we can think of speed and velocity as being the same thing. Therefore, the kinetic energy of an object is proportional to the square of its velocity (speed). In other words, If there is a twofold increase in speed, the kinetic energy will increase by a factor of four.

Explanation:

acceleration = (change in speed) / (time for the change)

change in speed = (20-120)= -100 m/s.

1.5 min = 90 sec

acceleration = -100/90 = -1.11 m/s^2.

we don't care about the 150kg or the 2,500 meters. they don't make any difference.

read more on -

the answer is b, have negligible mass