Question

if the momentum of a body decreases by 30% its kinetic energy decreases by ​

Answer 1

Answer:

Explanation:

ke=p^2/2m

applying errors we get

del ke / ke = 2 del p / p + del m /m

del m /m=0 because change in mass is 0

therefore del k / k=2(30)

del k /k =60%

Answer 2

Answer:\

k.e=1/2mvsq

p=m.v

in k.e multiply denominator and numerator by m

e=1/2 msq vsq/m

e=1/2psq/m

considering mass to be constant,if p is decreased by 30%then

new p=p-30/100p=0.7p

and

newk.e=(0.7p)sq/2m             we know k.e=(1/2mvsq)

new k.e=0.49psq/2m

%age decrease in  k.e=(k.e-new k.e)/k.e

there for decrease in k.e =51%

Explanation: