Question

A ball of mass 50g is thrown upwards . if rises to a maximum height of 100m. its K.E. reduced to 70% at height 10xn meter . Find the value of n?

Answer 1

H= u²/2g
H=u²/2g - v²/2g
=0,3u²/2g
=30 m

Answer 2

total energy will be conserved and here total energy is

mgh=0.005*10*100=50J

and 70 of K.E is 35 J

so

mgx+70% K.E = 50

it implie

s mgx =50-35 i.e.

x=30m