Work Done by Father on Girl's Sled Up Hill

  • Thread starter Thread starter colts2775
  • Start date Start date
  • Tags Tags
    Friction Work
AI Thread Summary
A father pushes his daughter's sled up a snowy incline at a constant velocity, requiring an analysis of the work done against gravitational and frictional forces. The height of the hill is 3.6 meters, with a mass of 35 kg for the girl and sled combined, and a coefficient of kinetic friction of 0.20. To calculate the work done, the force parallel to the motion must be determined, factoring in both gravity and friction. The work done is calculated using the formula W = mgh, resulting in a total of 2300 J. Understanding the components of motion and forces involved is crucial for solving this problem effectively.
colts2775
Messages
1
Reaction score
0

Homework Statement



A father pushes horizontally on his daughter’s sled to move it up a snowy incline. If the sled moves up the hill with a constant velocity, how much work is done by the father in moving it from the bottom to the top of the hill? The angle is 15 degrees, the top of hill is 3.6 meters high, the mass of girl and sled is 35 kg, and the coefficient of kinetic friction is 0.20.

Homework Equations





The Attempt at a Solution



I know that you have to sum the x and y components, and I know the y component is W=mgh=(35kg)(9.8 m/s^2)(3.6 m), and I know the final answer is 2300 J but I don't know how to get there.
 
Physics news on Phys.org
Work relates to the force parallel to the motion. Find that force first (i.e. turn the problem into a 1-d problem). Then find the distance of the motion. in this problem, it's easier that way... the motion is in a straight line against a constant force (caused by gravity in part and friction in part).
 
Kindly see the attached pdf. My attempt to solve it, is in it. I'm wondering if my solution is right. My idea is this: At any point of time, the ball may be assumed to be at an incline which is at an angle of θ(kindly see both the pics in the pdf file). The value of θ will continuously change and so will the value of friction. I'm not able to figure out, why my solution is wrong, if it is wrong .
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top