# NationStates Jolt Archive

## Killer Physics Problem

Cremerica
08-11-2005, 09:38
oof, can any one show me how to do this?

A sledge loaded with bricks has a mass of 18.0 kg and is pulled at a constant speed by a rope. The rope is inclined 20.0 degrees about the horizontal, and the sledge mose a distance of 20.0 m on a horizontal surface. The coefficent of kinetic friction is between the sledge and the surface is .5000.

a. what is the tension of the rope
b. how much work is done by the rope
c.what is the mechanical energy lost due to friction

ugh, i kept getting 94.9 for the tension of the rope. but i know thats not the right answer
Pantylvania
08-11-2005, 10:21
1. The vertical component of the force from the rope is tension * sin(theta). 2. The horizontal component is tension * cos(theta).
3. The normal force between the sledge and the surface is 18.0 * 9.81 - (tension*sin(theta)).
4. The frictional force is -0.5 * (18.0 * 9.81 - (tension*sin(theta))).
5. The horizontal component of the acceleration is 0.
6. Combine 2, 4, and 5. Then solve for the tension.