Question

The mass of a moving object increases, but its speed stays the same. What happens to the kinetic energy of the object as a result? A.It decreases. B. It increases. C. It remains unchanged. D. It fluctuates up and down.

Answer 1

The correct answer is 
B It increases.

In fact, the kinetic energy of a moving object is given by
$K= \frac{1}{2}mv^2$
where m is the mass of the object and v is its speed. We see that the kinetic energy is proportional to the mass and proportional to the square of the speed: in this problem, the speed of the object remains the same, while its mass increases, therefore the kinetic energy will increase as well.