The work done by Joe is 0 J.
<u>Explanation</u>:
When a force is applied to an object, there will be a movement because of the applied force to a certain distance. This transfer of energy when a force is applied to an object that tends to move the object is known as work done.
The energy is transferred from one state to another and the stored energy is equal to the work done.
W = F . D
where F represents the force in newton,
D represents the distance or displacement of an object.
Force = 0 N, D = 20 cm = 0.20 m
W = 0
0.20 = 0 J.
Hence the work done by Joe is 0 J.
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Answer:
IMA = 2.5 metres
EFFICIENCY = 80%
Explanation:
The AMA of a machine is referred to as the Actual Mechanical Advantage of a machine, calculated as the ratio of the output to the input force.
The Ideal Mechanical Advantage is the ratio of the input distance to the output distance.
From the diagram, the input distance which is also the distance moved by effort = 5metres
The load distance (output distance) = 2 metres
IMA = INPUT DISTANCE / OUTPUT DISTANCE
IMA = 5metres / 2 metres = 2.5 meters
Efficiency is the ratio of AMA TO IMA
AMA = 2, IMA = 2.5
EFFICIENCY = AMA / IMA
EFFICIENCY = (2 / 2.5) × 100%= 0.8 × 100%
EFFICIENCY = 80%
Answer:
68cm
Explanation:
You can solve this problem by using the momentum conservation and energy conservation. By using the conservation of the momentum you get

m: mass of the bullet
M: mass of the pendulum
v1: velocity of the bullet = 410m/s
v2: velocity of the pendulum =0m/s
v: velocity of both bullet ad pendulum joint
By replacing you can find v:

this value of v is used as the velocity of the total kinetic energy of the block of pendulum and bullet. This energy equals the potential energy for the maximum height reached by the block:

g: 9.8/s^2
h: height
By doing h the subject of the equation and replacing you obtain:

hence, the heigth is 68cm
The answer is D. time really does pass more slowly in a rest frame of reference relative to a frame of reference that is moving