Question

a ball of mass 100 gram is thrown upward it rises to maximum height of hundred metre what is the kinetic energy will be reduced to 60 %​

Answer 1

mass of ball = 100gm

height = 100m

final velocity= 0

initial K.E = 1/2mu²

final K.E = 1/2mv²

change in K.E=60%

(1/2mv² - 1/2mu²)%of K.E =60% K.E

=>1/2m(v²-u²) = 60

=>1/2*100/1000(-u²)=60

=>1/20(-u²)=60

=> -u²=60*20

=>u²=1200

=>u=√1200= 20√3m/s

•°•K.E => 1/2mu²= 1/2*1/10 *1200=60J

hence, initial K.E => 60J

Answer 2

I HOPE THIS IS HELPFUL.....

Thank you∆√