Question

A boy in a wheelchair (total mass, 46.9kg) wins a race with a skateboarder. He has a speed of 1.30m/s at the crest of a slope 2.35m high and 12.6m long. At the bottom of the slope, his speed is 6.28m/s. If air resistance and rolling resistance can be modeled as a constant frictional force of 41.3N, calculate the work he did in pushing forward on his wheels during the downhill ride

Answer 1

energy at crest ... (1/2 m Vc^2) ... Ec

energy at bottom ... (1/2 m Vb^2) ... Eb

Eb = Ec + (m g h) + work - (12.6 * 41.3)

Answer 2

So should I substitute work or calculate Eb?
Then is it work minus 12.6*41.3 or work=12.6*41.3?
Bit confused there. Thank you

Answer 3

https://www.jiskha.com/display.cgi?id=1508888603

Answer 4

you have all the values except the work

that's what the question asks for

work = Eb - Ec - (m g h) + (12.6 * 41.3)