A team of dogs drags a 123 kg sled 1780 m over a horizontal surface at a constant speed. The coefficient of friction between the sled and the snow is 0.209. The acceleration of gravity is 9.8 m/s^2.
1)Find the work done by the dogs. Answer in units of kJ.
2)Find the energy lost due to friction. Answer in units of kJ.
2007-06-21 12:35:07 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Physics
1. W = F x D.
The way to incorporate the frictional force into the equation is simply that the dogs pull the sled at a constant rate; by summing the forces, you can see that the only forces acting ont he cart are gravity, frictional force, and the force due to the dogs. the force the dogs exert on the sled will be equal and opposite to the frictional force. F = [mu] * Fn.
2. This can be done by simply energy conservation.
E = E'.
2007-06-21 12:46:04 · answer #1 · answered by weeezin da juice 2 · 0⤊ 0⤋
since there is no change in elevation or speed, the energy lost to friction is the only work done.
Friction force overcome = weight (mg) x coef of fric given.
Work = force x distance.
the energy lost to friction is implied to be equal to the work done because there is no other change in energy...
2007-06-21 19:47:51 · answer #2 · answered by Piglet O 6 · 0⤊ 0⤋
guy has been needing equations for hours
2007-06-21 20:26:42 · answer #3 · answered by bombaybubba 3 · 0⤊ 0⤋