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
Imma go with A.
Hope this helps:)
Q9. Inertia is the tendency of an object to resist any change in its motion.
Q10. A moving object's momentum depends on the object's mass and velocity.
Q11. I believe it would be air resistance. The fluid friction that opposes the motion of object's through the air.
Answer:
If the mass is doubled the frequency will be multiplied by 4
