Exams › JEE Main › Physics

A machine gun fires bullets of mass 10 g each at a rate of 60 bullets per minute, the muzzle speed of each bullet being 100 m/s. What is the thrust (reaction force) experienced by the person who holds the gun steady?

1. 1 N
2. 6 N
3. 10 N
4. 60 N

Correct answer: 1 N

Solution

60 bullets/min = 1 bullet/s, so dm/dt = 0.01 kg/s; thrust F = v*(dm/dt) = 100*0.01 = 1 N.

Related JEE Main Physics questions

• Which of the following has the same SI unit as impulse?
• A monkey slides downward from a tree branch with uniform acceleration. If the maximum tension the branch can withstand is 75% of the monkey’s weight, what is the least downward acceleration that will allow the monkey to descend without snapping the branch?
• A 1000 kg car is travelling at 30 m/s. The brakes are applied until it stops. If the friction force between the tyres and the road is 5000 N, how long will the car take to come to rest?
• A rocket initially ejects gas from its rear at a mass rate of 0.1 kg s⁻¹. If the exhaust speed relative to the rocket is 50 m s⁻¹ and the rocket’s mass is 2 kg, what is its acceleration in m s⁻²?
• A block of mass M rests on a rough level floor with coefficient of friction μ. A person applies a horizontal pull, but the block remains at rest. If the total contact force exerted by the floor on the block is F, then
• Which of the following types of motion on a frictionless plane surface occurs without any force acting on the body?

⚔️ Practice JEE Main Physics free + battle 1v1 →