Answer:
direct current hope this helped : )
Well, the 20 seconds gives us enough information to actually calculate the power she has on her feet :)
Well, the work is 500*15=7500J, that is 7.5 kJ or about 18 calories (1 cal is 418J?) The power is that 7.5 kJ divided by 20 seconds: 375W. That's... OK, I suppose...
Answer:
The work done by the worker on the crate is 4830 J.
Explanation:
Given that,
Force = 1080 N
Horizontal force = 345 N
Distance d = 14 m
Coefficient of friction = 0.22
We need to calculate the work done
Using formula of work done

F = force
d = distance
Put the value into the formula


Hence, The work done by the worker on the crate is 4830 J.
I think the correct answer would be the child quietly sits until the timer goes off. It is ineffective because the child would be used to this process and would come to a time where he will not get something from it.Also, it would make a child feel isolated and alone which would affect hi self-esteem in a long run.