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M2 Work, energy and power help, question included.

A girl and her sledge have a mass of 40kg. She starts from rest and descends a slope which is incline at 25 degrees to the horizontal. At the bottom of the slope the ground becomes horizontal for 15 meters before rising at 6 degrees to the horizontal. The girl travels 25 meters up the slope before coming to rest once more. There is a constant resistance to motion of magnitude 18 Newtons. Calculate the distance the girl travels down the slope.

The answer is 11.8 meters. But i am lost as to how to get there.


Please help!

You have to use the conservation of mechanical energy and the work energy principle.
Original post by UsamaS
A girl and her sledge have a mass of 40kg. She starts from rest and descends a slope which is incline at 25 degrees to the horizontal. At the bottom of the slope the ground becomes horizontal for 15 meters before rising at 6 degrees to the horizontal. The girl travels 25 meters up the slope before coming to rest once more. There is a constant resistance to motion of magnitude 18 Newtons. Calculate the distance the girl travels down the slope.

The answer is 11.8 meters. But i am lost as to how to get there.


Please help!

You have to use the conservation of mechanical energy and the work energy principle.


So mgh = Fd

40×9.8×(xsin⁡25−25sin⁡6)=18×(x+15+25)40 \times 9.8 \times (x \sin 25 - 25 \sin 6) = 18 \times (x+15+25)
Original post by UsamaS
A girl and her sledge have a mass of 40kg. She starts from rest and descends a slope which is incline at 25 degrees to the horizontal. At the bottom of the slope the ground becomes horizontal for 15 meters before rising at 6 degrees to the horizontal. The girl travels 25 meters up the slope before coming to rest once more. There is a constant resistance to motion of magnitude 18 Newtons. Calculate the distance the girl travels down the slope.

The answer is 11.8 meters. But i am lost as to how to get there.


Please help!

You have to use the conservation of mechanical energy and the work energy principle.


You'll only help yourself (a lot!) if you draw a diagram and label it thoroughly.

Once you've done that, recall the principles of energy and WD from the textbook/your notes.
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UsamaS
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Original post by Mr M
So mgh = Fd

40×9.8×(xsin⁡25−25sin⁡6)=18×(x+15+25)40 \times 9.8 \times (x \sin 25 - 25 \sin 6) = 18 \times (x+15+25)



You are awesome thank you so much, so annoyed that i did not see that
Original post by UsamaS
You are awesome thank you so much, so annoyed that i did not see that


Ok good.

:smile:

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