This is my problem(adsbygoogle = window.adsbygoogle || []).push({});

A 15 kg child slides, from rest, down a playground slide tht is 4.0 m long, as shown in the figure. The slide makes a 40 degrees angle with the horizontal. The child's speed at the bottom is 3.2 m/s. What was teh force of friction that the sldie was exerting on the child?

Ok. The answer in the texbook says 75N.

Here is my WROng attempt

work=Kinetic Energy 2 - Kinetic Energy 1

work = 1/2 m (V2squared - v1squared)

w=1/2 (15 kg) (3.2 m/s squared - 0)

w=7.5 (10.24 m/s)

w=76.8 J

then I..

Work=force (distance) (cos40)

f= w/d (cos 40)

f=76.8 J / 4.0 (cos 40)

f=14.7 N

Where is my error.. HELP PLEASE

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Force of Friction

**Physics Forums | Science Articles, Homework Help, Discussion**