Home
Class 11
PHYSICS
A block moving horizontally on a smooth ...

A block moving horizontally on a smooth surface with a speed of 40 m/s splits into two parts with messes in the ratio of 1:2 If the smaller part moves at 60 m/s in the same direction , then fractional change in kinetic energy is :

A

`(1)/(3)`

B

`(2)/(3)`

C

`(1)/(4)`

D

`(1)/(8)`

Text Solution

Verified by Experts

The correct Answer is:
D

`m xx 40= (2)/(3) mv+ (m)/(3) xx 60`
120= 2v+60
v= 30m/s
Now `K_(i)= (1)/(2) xx m xx 40^(2)= 800m`
`K_(f)=(1)/(2) xx (2m)/(3) (0)^(2)+ (1)/(2) xx (m)/(3) xx (60)^(2)`
`=(1)/(6) {m(1800+3600)}= (m(5400))/(6)= 900m`
`(Delta KE)/(K_(i))= (900m- 800m)/(800m)= (1)/(8)`
Promotional Banner

Similar Questions

Explore conceptually related problems

A block moving horizontally on a smooth surface with a speed of 40 ms^(-1) splits into two equal parts. If one of the parts moves at 60 ms^(1) in the same direction, then the fractional change in the kinetic energy will be x : 4 where x =__________

A block movig horizontally ona smooth surace with a speed of 20 m/s bursts into thwo equal parts cobtinuing in the same direction. If one of the parts moves at 30 m/s, with whast speed does the second part move and what is tehfractional change in the kinetic energy?

A particle is moving along x-axis with velocity 40 m/s. It breaks into two parts in mass ratio 1:2. If speed of smaller part is 60 m/s along x-axis then find fractional changes in kinetic energy of system.

Relative speed of two persons moving with u m/s and m/s in same direction where u>V

A block A of mass 2 kg is moving to right with a speed of 5 m/s on a horizontal smooth surface. Another block B of mass 2 kg, with a mass less spring of force constant K =200 N/m attached to it, is moving to left on the same surface with a speed of 3 m/s. Block A collides with the spring attached to B. Calculate (a) the final velocity of the block A. (b) the minimum kinetic energy of the system of two blocks during subsequent motion. (c) Repeat part (b) if there is no spring and the two blocks collide head on. Assume that the blocks are made of perfectly elastic material

A block of 10 kg mass is thrown on a rough surface having friction coefficient 0.3 with an initial speed of 5 m/s. Find the amount by which the internal energy of the blocked and the surface will increase. If this block is seen from a frame moving at a speed of 5 m/s in the direction of its velocity it is observed that the block is gently put on the rough surface moving in opposite direction at speed 5 m/s. Find the gain kinetic energy of the block as seen from this frame.

Two objects having equal masses are moving with uniform velocities of 2 m/s and 6 m/s respectively. Calculate the ratio of their kinetic energies.

A 15kg block is initially moving along a smooth horizontal surface with a speed of v=4m//s to the left. It is acted by a force F , which varies in the manner shown. Determine the velocity of the block at t=15 seconds.

A particles has velocity 40 m/s is exploded into two equal parts one with 60 m/s in same direction. The ratio of kinetic energy of individual particles after explosion is K:4, Then K is