Question

Two balls $A$ and $B$ are thrown with same velocity $u$ from the top of a tower Ball $A$ is thrown vertically upward and the ball $B$ is thrown vertically downward. Choose the correct statement.

• A. Ball $B$ reaches the ground with greater velocity
• B. Ball$A$ reaches the ground with greater velocity
• C. Both the balls reach the ground with same velocity
• D. Cannot be interpreted

Answer 1

The correct option is C Both the balls reach the ground with same velocity

We know,

The direction of motion while touching the ground will be vertically downwards,

Now coming to the speed,

Speed is nothing but a reflection of Kinetic energy of a body,

More the kinetic energy more the speed.

Taking the ball-earth system,

Mechanical energy is conserved,

Gain in Kinetic energy=loss in potential energy

And as both the balls are at same height,

Irrespective of the initial direction of throw,

Both will lose same potential energy and gain the same Kinetic energy,

Hence having the same velocity when they are near the ground.

Option $\text{C}$ is the correct answer