Grade 11Mechanics

A ball after freely falling from a height of 4.9 m, hits a horizontal surface. If e=3/4, Then the ball will hit the surface, second time after ; a} 1sec b} 1.5sec c}2sec d}3sec

ravi

4 Years agoGrade 11

1 Answer

Ayush Kumar

4 Years ago

Hello dear

The question which you are asking is a bit related to kinematics and a bit related to collision

Just remeber some equations i.e.

Time period of an object=2u/g where u is the initial velocity

Velocity of an object when it reaches the ground9if it is going under free fall)=root under 2gh

e=velocity of seperation/velocity of approach

Now,

Velocity of approach =root under 2*9.8*4.9=9.8

e=3/4

Velocity of seperation=3/4*9.8

Time period=2*u/g

now u=velocity of seperation=3/4*9.8

T=2*3*9.8/4*9.8

T=1.5sec

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A ball after freely falling from a height of 4.9 m, hits a horizontal surface. If e=3/4, Then the ball will hit the surface, second time after ; a} 1sec b} 1.5sec c}2sec d}3sec

ravi

1 Answer

Ayush Kumar

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