(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

A man of mass 70kg rides a bicycle of mass 15kg at a steady speed of 4.0 ms^{-1}up a road which rises 1.0m for every 20m of its length. What power is the cyclist developing if there is a constant resistance to motion of 20 N? Take g as 10 ms^{-2}if necessary.

(The answer given in the book is 2.5x10^{2}W)

2. Relevant equations

power = work done/time taken

work done = force x distance moved in direction of force = force x velocity

w= mg

3. The attempt at a solution

I really can't get anywhere with this one after about 45 mins. I know I will kick myself. At first I made an attempt to find the angle of the slop using trigonometry and got a value of 2.9 degrees but this got me nowhere. I'm pretty sure I need to multiply the combined mass of 85 kg by the 1m rise in order to find the value of the work done against gravity. 85 x 10 = 850 N. I tried constructing a right-angled triangle with a hypotenuse of 20m and gave the side with a 1m rise a value of 850 N. But again this got me nowhere. I think the problem is calculating the force on the flat when the cyclist is travelling at 4ms^{-1}but I don't know how to do this in order to add that value onto the vertical component. My humble, frazzled brain could use some assistance.

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# Homework Help: Power, Motion & Slopes

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