Question

The Grinch is trying to push a 5000-kg sled up the side of Mount Crumpit (whose side make an angle of 60 degrees above the horizontal) when he suddenly loses his grip and lets go of the sled. The sled starts sliding back down and soon afterwards hits a tree with an impact speed of 60 m/s, three hundred meters further down the slope.

Find the amount of gravitational potential energy that has been lost during the slide (in J).

How much kinetic energy has the sled gained during the slide?

The force responsible for the overall loss of mechanical energy is

A. normal force
B. weight
C. static friction
D. kinetic friction

The missing mechanical energy has been

A. lost for good
B. turned to kinetic energy
C. turned to potential energy
D. turned to thermal energy

Answer 1

Step-by-step explanation:

height lost h = 300 sin60

= 259.8 m .

gravitational potential energy = mgh

= 5000 x 9.8 x 259.8

= 1273 x 10⁴ J

Kinetic energy

= 1/2 mv²

= .5 x 5000 x 60²

= 900 x 10⁴ J

there is loss of kinetic energy = 373 x 10⁴ J.

This loss in energy is due to kinetic friction that came into action when the sled slipped downwards.

The lost energy is converted into heat energy or thermal energy.