The work done will be equal to the potential energy of the piano at the final position
P.E=m.g.h
.consider the plank the hypotenuse of the right triangle formed with the ground
.let x be the angle with the ground=31.6°
.h be the side opposite to the angle x (h is the final height of the piano)
.let L be the length of the plank
sinx=opposite side / hypotenuse
= h/L
then h=L.sinx=3.49×sin31.6°=0.638m
weight w=m.g
m=w/g=3858/10=385.8kg
Consider Gravity g=10m/s2
then P.E.=m.g.h=385.8kg×10×0.638=2461.404J
then Work W=P.E.=2451.404J
Answer:
Please check the attached file for the diagram
Explanation:
The velocity of the of the rowboat 
through the river is the resultant velocity. It is obtained taking a vector sum of the velocity in still water and the velocity of the river.
There are several ways to take this vector sum, but the question makes it simple for us to use Pythagoras's theorem because the East and North directions are perpendicular to each other.
Hence;
15x 9.8 x .3 = 44.1
15 x 9.8 x 1 = 147
147 - 44.1 = 102.9J
102.9 J
Awnser:
Elastic Potential Energy. Elastic potential energy is Potential energy stored as a result of deformation of an elastic object,
Explanation:
