Answer:
depende de que fenómenos nos referimos de acuerdo al los cuerpos de formación puede aver movimiento contante
Answer: 14.7kJ, 29.4kJ, 44.1kJ
Explanation:
<em>The gravitational potential energy is the energy that a body or object possesses, due to its position in a gravitational field. </em>
<em />
In the case of the Earth, in which the gravitational field is considered constant, the value of the gravitational potential energy 
will be:
Where 
is the mass of the object, 
the acceleration due gravity and 
the height of the object.
Knowing this, let's begin with the calculaations:
For m=3kg
For m=6kg
For m=9kg
Answer:
Explanation:
(ΔK + ΔUg + ΔUs + ΔEch + ΔEth = W)
ΔK is increase in kinetic energy . As the athelete is lifting the barbell at constant speed change in kinetic energy is zero .
ΔK = 0
ΔUg is change in potential energy . It will be positive as weight is being lifted so its potential energy is increasing .
ΔUg = positive
ΔUs is change in the potential energy of sportsperson . It is zero since there is no change in the height of athlete .
ΔUs = 0
ΔEth is change in the energy of earth . Here earth is doing negative work . It is so because it is exerting force downwards and displacement is upwards . Hence it is doing negative work . Hence
ΔEth = negative .
b )
work done by athlete
= 400 x 2 = 800 J
energy output = 800 J
c )
It is 25% of metabolic energy output of his body
so metalic energy output of body
= 4x 800 J .
3200 J
power = energy output / time
= 3200 / 1.6
= 2000 W .
d )
1 ) Since he is doing same amount of work , his metabolic energy output is same as that in earlier case .
2 ) Since he is doing the same exercise in less time so his power is increased . Hence in the second day his power is more .
