A grade 12 physics dynamics problem

AI Thread Summary
The discussion revolves around a physics problem involving a boy pulling a sled up a hill and later sliding down. The sled is dragged with a force of 35 N at a 35-degree angle on a 15-degree incline, and the task is to find the coefficient of kinetic friction and the boy's acceleration when sliding down. Participants express difficulty in applying angles to determine the forces acting on the sled, particularly in calculating the normal force and frictional force. Suggestions include drawing a free body diagram (FBD) and using symbolic representations for values to simplify calculations. Understanding the forces' magnitudes and directions is crucial for solving the problem effectively.
Scatteredheroes
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Homework Statement


A boy drags his 80 n sled at a constant speed up a 15 degree hill. He does so by pulling with a 35 n force on a rope attached to a sled. If the rope is inclined at 35 degrees to the horizontal, what is the coefficient of kinetic friction between snow and sled

At the top of hill, he jumps on sled (weighing 50 kg, the boy) and slides down the hill. What is his acceleration?

Homework Equations



Fnet= ma

Ffk = mew fn

And so on, so forth.

The Attempt at a Solution


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I drew a FBd, including angles, and force locations, but I do not know how to use the angles to find the required forces. As well, as a general question, how do you use angles in the diagram to find things?
 
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My main problem is that I know the Fg, which is ma (9.8)

After that, I get slightly lost due to the angles, and am unable to find even the most basic fn.
 
Scatteredheroes said:
I drew a FBd, including angles, and force locations, but I do not know how to use the angles to find the required forces.
if you can't post the diagram, at least try to describe it. What forces operate, what magnitudes and what directions?
Invent symbols for all values so that the algebra can be done symbolically. Only plug the numbers back in at the end.
 
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