Question 19 of 308
Given below are two statements:
Statement I : A truck and a car moving with same kinetic energy are brought to rest by applying breaks which provide equal retarding forces. Both come to rest in equal distance.
Statement II : A car moving towards east takes a turn and moves towards north, the speed remains unchanged. The acceleration of the car is zero.
In the light of given statements, choose the most appropriate answer from the options given below
Show answer and solution
Answer: (A) Statement I is correct but statement II is incorrect
The work done in stopping the car and the truck can be written as
As both the car and the truck are moving initially with the same kinetic energy, after being stopped, they will have the same change of kinetic energy.
Also, they are stopped with the same applied force.
Hence, from the above equation, it can be written that they have the same displacement, i.e., .
Acceleration is a vector quantity. As the direction of motion of the car is different in the two given situations, the acceleration of the car will not be the same.
As both the car and the truck are moving initially with the same kinetic energy, after being stopped, they will have the same change of kinetic energy.
Also, they are stopped with the same applied force.
Hence, from the above equation, it can be written that they have the same displacement, i.e., .
Acceleration is a vector quantity. As the direction of motion of the car is different in the two given situations, the acceleration of the car will not be the same.
