Question

calculate the kinetic energy of a body if the velocity of body is made half the original.Original kinetic energy is 800 joules?

Answer 1

1/2mv^2=800..........................(1)
now,
1/2m(v/2)^2 = 1/2*m(v^2/4)
(1/2mv^2)/4
on substituting from (1)
800/4
200
so the answer is 200 joules

Answer 2

kE = 1/2 mv^2
800 = 1/2 mv^2
v =
$\sqrt{400 \div m}$
now velocty = 1/2 v
KE = 1/4 mv^2.
now to can find answer