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:
87.1 mph
Explanation:
We are given that
Mass,m=60 kg
Power,P=340 W
Speed,v=5 m/s
Area,
Drag coefficient,
Coefficient of rolling resistance,
Friction force,
Where 
Let speed of cyclist=v'
Drag force,
Density of air,

Power,P=



1 m=0.00062137 miles
1 hour=3600 s
100N to the left. Newton's 3rd law action and reaction
Answer: Not 100% sure but I think it’s C.
Hope this helps! ^^