Question

A child with a mass of 29.4 kg sits in a sled at the top of a hill that is 13.7 m high. Assuming no energy is lost to friction as the child slides down hill, what is the child's kinetic energy at the bottom of the hill?

a. 3.50e+3J

b. 2.40e+3J

c. 2.63e+3J

d. 3.95e+3J

e. 2.98e+3J

Answer 1

Since no energy is lost to fraction.

So using conservation of the energy

   Kinetic energy = change in the potential energy

K=mgH

here m=29.4kg H=13.7 m , g=9.81 m/s^2

K=29.4×9.81×13.7

K=3951.2718 J

K=~3.95×10^3 J

so correct answer is (d) .