A student eats a dinner containing 8.0x10 raised to power 6j of energy. He wishes to do an equivalent amount of work in a nearby gym by lifting a 60kg object.
How many times must he raise the object to expand this much energy? Assume that he raises it a distance of 2.0m each time.
We know; E=8 million joules, M=60kg, S=2.0m,
With these data above we have to reason that the student possesses an energy of 8million joules in him....so we have to find his workdone from lifting the 60kg object......therefore the force which he will use will be;F=60kg*10m/s^2(due to gravity)=600N
Therefore, our work is...
W=600N*2.0m=1200J
Now we know the work he did to lift that 60kg object...
Now for him to expand 8millionj of energy in the gym
8millionJ must be equal to d work he does...therefore
8millionJ=1200J....therefore....
8million/1200=6.7*10^3 times
There you have it...
N*2*9.8*60=8E6
N=8E6/1.18E3=6.8E3 times. I bet he messes up his count.