Question

A car is driving South at 30 Mi/h, when the driver steers bringing the car to head West still moving at 30 Mi/h. Which of the following statements is the only CORRECT one

Answer 1

Answer:

D. The linear momentum of the car changed, its kinetic energy did not change.

Explanation:

A. The linear momentum of the car changed, its kinetic energy changed.

B. The linear momentum of the car did not change, its kinetic energy did not change.  

C. The linear momentum of the car did not change, its kinetic energy changed.

D. The linear momentum of the car changed, its kinetic energy did not change.

As we know that the direction of motion of the car is changed from South to West so here momentum is not conserved as momentum is a vector quantity

While we know that kinetic energy is given as

$k = \frac{1}{2}mv^2$

so here kinetic energy is a scalar quantity which remains conserved as none of the magnitude changed here

So correct statement is

D. The linear momentum of the car changed, its kinetic energy did not change.