Yes. Think of block sitting on top of a bigger block. If the bottom block moves, it will drag the top block with it. Since the force of friction on the small block and its displacement are in the same direction, the "work" is positive. The static friction is a passive force, It is not a source of energy; it transmits the force placed on the bottom block. (And the "work" done by the friction on the bottom block is exactly the negative of the work done on the top block.)
Explanation:
a) The rope obeys Hooke's law, so:
F = k Δx
The elastic energy in the rope is:
EE = ½ k Δx²
Or, in terms of F:
EE = ½ F Δx
Use trigonometry to find the stretched length.
cos 20° = 35 / x
x = 37.25
So the displacement is:
Δx = 37.25 − 24
Δx = 13.25
The elastic energy per rope is:
EE = ½ (3.7×10⁴ N) (13.25 m)
EE = 245,000 J
There's two ropes, so the total energy is:
2EE = 490,000 J
Rounded to one significant figure, the elastic energy is 5×10⁵ J.
b) The elastic energy in the ropes is converted to gravitational energy.
EE = PE = mgh
5×10⁵ J = (1.2×10³ kg) (9.8 m/s²) h
h = 42 m
Rounded to one significant figure, the height is 40 m. So the claim is not justified.
Answer:
The velocity is 
Explanation:
From the question we are told that
The diameter of the pipe is 
The magnetic field is 
The hall voltage is 
Generally the average fluid velocity is mathematically represented as
=> 
=>
