Question

(Please please please help!) A 38kg child is at the top of a slide that is 2.1m tall.

(a) If there is no friction, how fast will they be moving when they reach the bottom of the slide?
(b) If they lose 250.0J of energy to sound, heat, and friction, how fast will they be moving when they reach the
bottom?

Answer 1

A). Since No friction is present...

All Gravitational potential Energy is converted to Kinetic

Using g=10ms-²

1/2mv²=mgh

1/2v²=gh

v²=2gh

v=√2gh

v√2(10)(2.1)

v=6.48ms-¹

B). 250J is lost....

The Energy on the Body =Total Energy – Lost Energy

Mgh - 250

380(10)(2.1) - 250

=548J

548J is the energy that would be transferred into speeding up the Child... The 250 is lost to other factors

PE Energy=1/2mv²

v²= 2PE/m

v=√2 x 548/(38)

v=√28.84

v=5.37ms-¹