Question

on 41. A 25 kg child plays on a swing having support ropes that are 2.2 m long. A friend pull back until the ropes are 42 degrees from the vertical and releases her from rest. (a) What is the potential energy of the child just as she is released, compared with the potential energy at the bottom of the swing? (b) how fast will she be moving at the bottom of the swing? (c) how much work does the tension in the rope do as the child swings from initial position to the bottom? s her 45. A 12 N package of whole wheat flour is suddenly placed on the pan of a scale such as you find in grocery stores. The pan is supported from below by a vertical spring of force constant 325 N/m. If the pan has negligible weight find the maximum distance the spring will be compressed if no energy is disipated by friction? Section7 4 7 A15 ke hrick is sliding along on a rough horizontal surface at 13m/s. If the brick stops in 4.8

Answer 1

As per HomeworkLib guide lines I am working first problem , please remaining questions in the next post

(a)

The potential energy at the bottom of the spring is

PE = mg h

= mg L ( 1- cos theta)

= 25* 9.8 *2.2 ( 1- cos 42)

=138.44 J

(b)

v= sqrt 2gh

= sqrt 2 gL(1- cos theta)

= sqrt 2 ( 9.8) ( 2.2) ( 1- cos 42)

=3.32 m/s

(c)

there is no displacment of the mass along the tension , so workdone by the tension in the rope is zero.