Vectors question!!!!

Question

anonymous · Answer

How much work is done against gravity by a workman carrying an 8kg sheet of plywood up a 3m ramp inclined at an angle at 20 degrees to the horizontal.

anonymous · Answer

The answer is 80J

mrnood · Answer

work done = mgh, where h is the height raised by the mass

mass =8kg
g= 9.81
from the drawing work out h

hence calculate work done

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anonymous · Answer

Work done = PE = mgh
sin20 = opposite side / hypotenuse
0.3420 = opposite side / 3m
opposite side = height = 1.026 meters high

Work = 8 kg * 9.8 * 1.026m = 80.4 Joules

mrnood · Answer

@biire2u - I had already given the OP all the info and guides to at least give the question some thought. The OP already had the answer - maybe leaving a little to think about would help the understanding .....