30 August, 14:50

You do 5 joules of work to move a 4 newton object 5 meters. find your efficiency.

+4
1. 30 August, 15:06
0
There's not enough information given in the question to answer it.

In order to calculate efficiency, we need to know not only how much

energy (work) was put into the job, but also how much useful energy

(work) was accomplished.

- - If the 4N object is moved horizontally without friction, then no work

was done on it at all. Spending 5 joules of energy to accomplish zero

work is about as inefficient as you can get. Zero. Or worse.

- - If the 4N object was lifted to a height of 5 meters, no matter what

route it took to get there, then the work done on it would have been

(4 x 5) = 20 joules. That could not have been accomplished with the

input of only 5 joules, so we know that the object could not have been

lifted to a height of 5 meters.

- - Now we know that the object was either pushed 5 meters horizontally

along a surface with some friction, or else pushed 5 meters up a ramp

to some unknown height.

Since neither the friction nor the final height is known, we

don't know how much useful work was accomplished, so we

can't calculate the efficiency.

Nyah nyah.