AQA Physics book page 152 Work-Energy mistake?
Hi can you check the answer to 4d. The Work done against friction.
The question says that a car of total mass 1200kg was travelling at 2m/s. It descends 50m down a track and the speed at the bottom is 28m/s. Calculate the work done against friction.
Work done = change in energy = loss of potential - gain in KE
I get 120KJ but the book quotes 122KJ. Can anyone confirm please?
The question says that a car of total mass 1200kg was travelling at 2m/s. It descends 50m down a track and the speed at the bottom is 28m/s. Calculate the work done against friction.
Work done = change in energy = loss of potential - gain in KE
I get 120KJ but the book quotes 122KJ. Can anyone confirm please?
Original post by tonym888
Hi can you check the answer to 4d. The Work done against friction.
The question says that a car of total mass 1200kg was travelling at 2m/s. It descends 50m down a track and the speed at the bottom is 28m/s. Calculate the work done against friction.
Work done = change in energy = loss of potential - gain in KE
I get 120KJ but the book quotes 122KJ. Can anyone confirm please?
The question says that a car of total mass 1200kg was travelling at 2m/s. It descends 50m down a track and the speed at the bottom is 28m/s. Calculate the work done against friction.
Work done = change in energy = loss of potential - gain in KE
I get 120KJ but the book quotes 122KJ. Can anyone confirm please?
i got 120kj too
It's just a case of how many sig figs you express the answer to. Not whether the answer is "correct" or not.
It will also depend on the value you use for g.
(9.8 or 9.81)
It will also depend on the value you use for g.
(9.8 or 9.81)
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