JEE Physics 2023 Question with Solution

Given: Two statements about stopping distance and acceleration during change of direction.

Find: Which option is correct.

For Statement I, use work-energy theorem:

$$\text{Work done} = \Delta KE$$

If the truck and the car have the same initial kinetic energy and the brakes provide equal retarding force, then the stopping work is the same. Hence,

$$F s = KE$$

Since $F$ is equal for both and initial $KE$ is equal, the stopping distance $s$ is equal for both vehicles. So Statement I is correct.

For Statement II, when the car turns from east to north, the speed remains unchanged but the direction of velocity changes. Velocity is a vector quantity, so change in direction means change in velocity.

$$\Delta \vec{V} = \vec{V_f} - \vec{V_i}$$

Therefore, acceleration is not zero:

$$\vec{a} \neq 0$$

So Statement II is incorrect.

The solution states The Correct Option is C, although it also concludes that the correct answer is $1$. Based on the solution authority line, the answer is taken as C.