Question

A person sitting at the rear end of the compartment throws a ball towards the front end. The ball follows a parabolic path. The train is moving with uniform velocity of $20m{s}^{-1}$. A person standing outside on the ground also observes the ball. How will the maximum heights $\left(h_m\right)$ attained and the range $\left(R\right)$ seen by the thrower and the outside observer compared to each other?

• A. Same $h_m$ and different $R$
• B. Same $h_m$ and $R$
• C. Different $h_m$ and same $R$
• D. Different $h_m$ and $R$

Answer 1

The correct option is A Same $h_m$ and different $R$

In the vertical direction the velocity of ball will remain same w.r.t both the observers. Therefore, $H=\frac{u_y^2}{2g}$ will remain same for both the observers. But in the horizontal direction, the velocity of ball observed by the person in the train will be with respect to his velocity (i.e., velocity of a moving train), so it will be different from the velocity of the ball observed by the person standing on the ground. Thus, range $(\text{i.e.}R=\frac{2u_x{u}_y}{g})$ observed by both the observers will be different.