help@askiitians.com

+91-87964 74404

Grade 8Mechanics

A machine gun fires a bullet of mass 40g with a velocity 1200 m/s. the man holding it can exert a maximum force 144 N on the gun. How many bullets can he fire per second at the most.

mohit

12 Years agoGrade 8

4 Answers

neeraj agarwal

12 Years ago

here, *The gun will exert an impulsive force on the man when it will be fired. * As force will be of impulsive nature I=MV * 40*10^-3*1200=48 N-s * the man can hold with a force of 144 N for 1 sec. * The force must be of impulsive nature. * no. of bullets=144/48=3.

Jai shiv naman

9 Years ago

Given that m= 40*10^-3,f=144N v=1200m/s We know that force = dp/dt means that change in momentum is called force Then p=mv hence f= d(mv)/dt but find out n bullets per seconds Then f=mvn/t 144=n *40*10^-3*1200/1 hence n=3

saa

7 Years ago

mass=40g=40*10^-3 kg

v=1200 m/s

F=144N

F is directly proportinal to dp/dt

f is equal to k*dp/dt

let k be no of bullets fired per second =n

t=1s

F=n*dp/dt

144=n*(40*10*-3*1200)/1

144/48000*10^-3=n

n=3

ankit singh

5 Years ago

Mass of each bullet = 40 g = .040 kg

Velocity of each bullet = 1200 m/s

Let 'n' be the number of bullets fired per second. Then, change in momentum of the bullets coming out per second is,

= force on the man

=> n (0.040)(1200) = 144

=> n = 3

Three identical balls are placed on a frictionless horizontal surface touching each other. They stick to each other because of adhesive. Another ball of same radius and mass m is placed over the void created by the three balls. Find the forces applied by the balls kept on the floor to each other if the system remains in equilibrium.

mechanics

1 Answer Available

Last Activity: 10 Months ago

A car loaded with water having total mass 1000 kg moves on a straight horizontal Road starting from rest under the action of a force of 100 Newton. The water spills throw a small hole in the bottom at a rate of 0.1 KG per second the velocity of cart after 300 seconds is nearly.

11
21
31
41

mechanics

1 Answer Available

Last Activity: 10 Months ago

A metal strip clamped at one end vibrates with a frequency of 20 Hz and amplitude of 5 mm
at the free end, where a small mass of 2 g is positioned. determine
(i) The velocity of the end when passing through the zero position
(ii) The acceleration at maximum displacement
(iii) The maximum kinetic energy of the mass

mechanics

2 Answers Available

Last Activity: 3 Years ago

An object of mass m = 0.25 kg oscillates in a fluid at the end of a vertical spring of spring
constant kH = 85 N/m, see Fig.1. The effect of the fluid resistance is governed by the
damping constant b = 0.07kg/s.
(i) Find the period of the damped oscillation.
(ii) By what percentage does the amplitude of the oscillation decrease in each cycle?

mechanics

1 Answer Available

Last Activity: 3 Years ago

If a=x² find the displacement at t =3sec if body velocity at t= 0 sec is 0

mechanics

1 Answer Available

Last Activity: 3 Years ago

View all Questions