Answer:
Work done, W = 5534.53 J
Explanation:
It is given that,
Force acting on the piano, F = 6157 N
It is pushed up a distance of 2.41 m friction less plank.
Let W is the work done in sliding the piano up the plank at a slow constant rate. It is given by :

Since,
(in vertical direction)

W = 5534.53 J
So, the work done in sliding the piano up the plank is 5534.53 J. Hence, this is the required solution.
Answer:
It often happens in a circuit which was conducting,and a switch is opened. Any inductance in the circuit will help the voltage increase due to back emf,and this can cause breakdown of the air insulation and an arc can form.
Explanation:
1.Light-collecting area
2.Angular resolution
If they're brought closer together