Answer:
c. an increase in the length of the rope.
Answer:
P = d g h pressure due to density of liquid of height h
d1 g h1 = d2 g h2 since P1 equals P2
d1 h1 = d2 h2 and the density of Hg is 13.6 times that of water
h2 = (d1 / d2) * h1 = 13.6 * 70 cm = 952 cm or 9.52 m
Answer: The elevator must be accelerating.
Explanation:
As the tension force is opposing to the the force of gravity on the load which is hung vertically, and the tension force can adopt any value in order to comply with Newton's 2nd law, if the tension force is less than the force due to gravity, this means that all system is not in equilibrium, so it must be accelerating.
If we assume that the downward is the positive direction, we can write:
mg - T = ma
If T = 0.9 mg, ⇒ mg (1-0.9) =0.1 mg = m a ⇒a = 0.1 g , in downward direction.
NB: The diagram of the pulley system is not shown but the information provided is sufficient to answer the question
Answer:
Power = 2702.56 W
Explanation:
Let the power consumed be P
Energy expended = E = mgh
height, h = 5 m
E = 80 * 9.8 * 5
E = 3920 J
To calculate the time, t
From F = ma
F = 900 N
900 = 80 a
a = 900/80
a = 11.25 m/s²
From the equation of motion, 
The drill head starts from rest, u = 0 m/s
Power, P = E/t
P = 3920/0.0.943
P = 4157.79 W
But Efficiency, E = 0.65
P = 0.65 * 4157.79
Power = 2702.56 W
Potential energy = (weight) x (height)
After the car has been raised 2.5 meters, it has
(11,000) x (2.5) = 27,500 Joules
MORE potential energy than it had before it was lifted.
That's the energy that has to come from the work you do to lift it.
Since no mechanical process is ever 100% efficient, the work required
to accomplish this task is <em>at least 27,500 joules</em>.
