A 100 lb block of ice slides down an incline 5.0 ft long and 3.0 ft high. A worker pushes up on the ice parallel to the incline so that it slides down at constant speed. The coefficient of friction between the ice and the incline is 0.10.
Find (a) the force exerted by the worker, (b) the work done by the worker on the block, (c) the work done by gravity on the block, (d) the work done by the surface of the incline on the block, (e) the work done by the resultant force on the block, and (f) the change in kinetic energy of the block.
I solved a and b, and I get them, but I'm stuck conceptually on the last few parts. On c, my biggest issue is that I think I'm confusing this situation to one where a block attached to a string is lowered (i.e. negative work is done on the block.)
Does (d) even matter since it's not the incline pushing the block down it? Or does friction play a part here?
For (e), if Fnet is 0 (since all the forces have to be 0 for there to be constant speed) does that mean this question is irrelevant?
...I can figure (f) out on my own.
I don't want answers, just...some conceptual help on this one.
sdzf
please help me:/
please give me the anwser of this:/
I can provide some conceptual explanations to help you understand the remaining parts of the problem.
(c) In the given situation, gravity is acting on the block as it slides down the incline. The work done by gravity is equal to the force of gravity multiplied by the displacement of the block along the incline. Since the displacement is in the same direction as the force of gravity, the work done by gravity is positive in this case. The formula for the work done by gravity is given by work = force × distance × cosθ, where θ is the angle between the force vector and the displacement vector. In this case, since the force of gravity and displacement are in the same direction, cosθ is equal to 1.
(d) The work done by the surface of the incline on the block is related to the friction force between the block and the incline. Friction always acts opposite to the direction of motion, so the work done by friction is negative. In this case, the friction force is acting up the incline, counteracting the downward force of gravity. The work done by the surface of the incline is equal to the force of friction multiplied by the displacement of the block along the incline. The formula for the work done by friction is given by work = force × distance × cosθ. Since the force of friction and displacement are in opposite directions, cosθ is equal to -1.
(e) The work done by the resultant force on the block is the sum of the work done by all the forces acting on the block. Since the block is sliding down the incline at constant speed, the net force on the block must be zero. Therefore, the work done by the resultant force is also zero. This means that the work done by the worker, gravity, and the incline surface must cancel out.
I hope these explanations help clarify the concept behind these parts of the problem. If you have more specific questions or require further assistance, please let me know.