Answer:243joules
Explanation:
Mass(m)=54kg
Velocity(v)=3m/s
Kinetic energy =(m x v^2)/2
Kinetic energy =(54 x 3^2)/2
Kinetic energy =(54 x 9)/2
Kinetic energy =486/2
Kinetic energy =243joules
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.
A. IMA: 4
The Ideal Mechanical Advantage (IMA) is given by:

where
is the input distance
is the output distance
For the pulley system in this problem,
and
, so the IMA is

B. MA: 3.59
The actual mechanical advantage (AMA), or simply the Mechanical Advantage (MA), is given by

where
is the output force and
is the input force. For the pulley system in this problem,
and
, so the MA is

C. Efficiency: 89.8 %
The efficiency of a machine is equal to the ratio between the MA and the AMA:

Therefore, in this case,

Answer:
35, I got you bro, i got you