Question

A balloon is moving with speed \(10\,m/s\) in upward direction. At height \(75\,m\) a stone is released then find distance travelled by stone in air.

• A. \(70\,m\)
• B. \(80\,m\)
• C. \(90\,m\)
• D. \(85\,m\)

Answer 1

The Correct Option is C

Concept: When the stone is released from the balloon, it already has the initial upward velocity of the balloon. The motion occurs in three stages: • Upward motion until velocity becomes zero • Downward motion back to release point • Further fall to the ground
Step 1:Find maximum additional height reached. \[ h = \frac{u^2}{2g} \] \[ h = \frac{10^2}{2 \times 10} \] \[ h = 5\,m \]
Step 2:Calculate total distance travelled. Upward distance: \[ AB = 5\,m \] Downward back to release point: \[ BC = 5\,m \] Height of balloon above ground: \[ CD = 75\,m \]
Step 3:Total distance travelled in air. \[ \text{Distance} = AB + BC + CD \] \[ = 5 + 5 + 75 \] \[ = 85\,m \] \[ \boxed{85\,m} \]