Question

A ball of mass 50 kg is thrown upwords. It rises to a maximum height of 100m. All what height its. kE is reduced to 70%?​

Answer 1

Explanation:

v

2

=u

2

+2as

0=u

2

+2(−10)(100)

u=

2000

=20

5

KE initially= 0.5mu

2

=0.5(0.05)(2000)=50J

0.7KE= 0.7(50)= 35J= 0.5mv

2

v=

2KE/m

=

2(35)/0.05

=

1400

v

2

=u

2

+2as

1400=2000+2(-10)s

s= 30m