Question

A Diwali cracker releases $25$ gram gas per second, with a speed of $400\,\text{m s^{-1}$ after explosion. The force exerted by gas on the cracker is}

• A. $100$ dyne
• B. $16$ newton
• C. $10$ newton
• D. $10{,}000$ dyne

Hint:

Thrust problems use rate of change of momentum directly.

Answer 1

The Correct Option is C

Step 1: Principle used.
Force is the rate of change of momentum:
\[ F = \frac{dm}{dt} \cdot v \]
Step 2: Converting given values.
\[ \frac{dm}{dt} = 25\,\text{g s}^{-1} = 0.025\,\text{kg s}^{-1} \] \[ v = 400\,\text{m s}^{-1} \]
Step 3: Calculating force.
\[ F = 0.025 \times 400 = 10\,\text{N} \]
Step 4: Conclusion.
The force exerted by gas on the cracker is $10$ newton.