# physics help

#1
how did they go question 27b(i)
https://gyazo.com/1edba33345e0ebe5c945c2244a0727c0
0
1 month ago
#2
What i did is
0.5*mass*velocity square + mass*9.81*vertical height = Work done required

So you will get the value as 4753.895168 J

Then you subtract it from the work done by the motor + cyclist
3700+5300 - 4753.895168
= 4246.104832 J of wasted energy
do 3 sf or 2 sf

4250 J
I hope this is the correct answer
0
#3
(Original post by Arkcano)
What i did is
0.5*mass*velocity square + mass*9.81*vertical height = Work done required

So you will get the value as 4753.895168 J

Then you subtract it from the work done by the motor + cyclist
3700+5300 - 4753.895168
= 4246.104832 J of wasted energy
do 3 sf or 2 sf

4250 J
I hope this is the correct answer
yes it is! thanks but why is it wasted work tho?
1
1 month ago
#4
Because the amount of work done that was needed was only 4753.895168 J
However, the motor and the cyclist required a total of 9000 J to get the job done. Therefore clearly the difference becomes the amount of energy wasted.
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