Question

a ball of mass 100g dropped from a height and reaches ground in 4sec.After hitting the ground,it rebounds with 80%of its K.E. .Find the height at which ball reaches after rebound.​

Answer 1

Explanation:

As we know that impulsive force is give by

F.t=m(V-U)

now we have to find the velocity before collision with ground

so mgh

1

=

2

1

mv

1

2

v

1

2

=

2gh

1

v

1

=7m/sec

again the velocity of ball after collision with ground will be

mgh

2

=

2

1

mv

2

2

v

2

2

=

2gh

2

v

2

=3.50m/sec

hence net velocity "V"=v

1

+v

2

=10.53m/sec

so from impulsive force equation we have to put all these value (U=0)

F=

t

m(V−U)

=

0.01

0.1(10.53)

=105.3 N