Question

When the velocity of projection of a body is made $n$ times, its time of flight becomes $n$ times. Range of projectile does not depend on the initial velocity of a body.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (C)

If assertion is true but reason is false

Answer 2

As time of flight, $T=\frac{2u \sin \theta}{g}$ $\therefore T'=\frac{2\left(nu\right) sin \theta}{g}=nT$ But range $R=\frac{u^{2} \sin 2\theta}{g}$ $\therefore R'=\frac{n^{2}u^{2} \sin 2\theta}{g}=n^{2}R.$