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 .
Answer:
Explanation:
When the springs are connected end to end, it means they are connected in series. When the springs are connected in series, the stress applied to the system gets applied to each of the springs without any change in magnitude while the strain of the system is the sum total of strains of each spring. The spring constant of the resultant system is given as,
Here, n = 10
Spring constant of each spring = k
Thus,
Answer:
The correct answer would be C, certain display rules are more appropriate than others.
Explanation:
I hope this helps you:)
Answer:
center of mass = −0.50 m
Explanation:
given data
mass m1 = 3.04 kg
distance xm = -8 m
mass m2 = 5.61 kg
distance xM = 3.56 m
solution
we get here center of mass for n mass of system that is express as
center of mass = 
......................1
but we have only 2 particle system so we will get
center of mass = 
.................2
put here value and we will get
center of mass = 
solve it we will get
center of mass = −0.50 m
Answer:
1.33
Explanation:
speed of light in vacuum, c = 3 x 10^8 m/s
speed of light in medium, v = 2.26 x 10^8 m/s
The refractive index of the medium is given by
μ = speed of light in vacuum / speed of light in medium
μ = (3 x 10^8) / (2.26 x 10^8)
μ = 1.33
