Question

A girl of mass 40 kg is travelling at a speed of 20m/s at the top of a 10m high roller coaster loop. Determine the girls total mechanical energy at the top of the loop. Assume the loss of energy due to friction and air resistance is negligible.​

Answer 1

Explanation:

Here,M=40kg, s=10m, v=20m/s, g=9.8m/s2

we know that M.E=K.E+P.E

Therefore we need to find kinetic energy and potential energy.

K.E=1/2mv2

K.E=1/2×40 (20)2

K.E= 1/2×40 (400)

K.E=20 (400)

K.E=8000J

Now,

P.E=mgh

P.E=40×9.8×10

P.E=3920J

THERFORE

M.E= K.E+P.E

M.E=8000+3920

M.E= 11920J