NEET Kinetic Energy and Momentum MCQs & PYQs

Practice NEET Kinetic Energy and Momentum Questions

Question 1:

easy

Assertion (A): A body cannot have kinetic energy without having linear momentum but it can have momentum without having mechanical energy.

Reason (R): Linear momentum and energy have same dimensions.

Assertion (A) is false:

If a body has linear momentum (\(p \neq 0\)), it must have velocity (\(v \neq 0\)), which implies it must also have kinetic energy (\(KE = \frac{1}{2}mv^2 \neq 0\)). Since kinetic energy is a component of mechanical energy, it cannot have momentum without mechanical energy.

Reason (R) is false: Linear momentum has dimensions \(MLT^{-1}\) while energy has dimensions \(ML^2T^{-2}\), which are different.

💬 Discuss this Question

Question 2:

easy

Assertion (A): Kinetic energy of a system can be increased without applying any external force on the system.

Reason (R): If external forces are absent then work done by internal forces is equal to change in kinetic energy.

According to the work-energy theorem, `\(W_{net} = \Delta KE\)`. If external forces are absent, the net work done on the system is only due to internal forces, i.e., `\(W_{int} = \Delta KE\)`. Thus, internal forces can increase kinetic energy, for example, in an explosion. Both assertion and reason are true, and the reason correctly explains the assertion.

💬 Discuss this Question