Answer:
(C) Only if it starts moving
Explanation:
We know that work done is given by
So there are two case in which work done is zero
First case is that when force and displacement are perpendicular to each other
And other case is that when there is no displacement
So for work to be done there must have displacement, if there is no displacement then there is no work done
So option (c) will be the correct option
The answer would be C. Gamma Rays and High Frequency EM waves travel at the speed of light and are transverse waves.
Answer:
wavelength 
= 437.27 nm
Explanation:
given data
first bright fringe = 2.96 mm
slit separation = 0.325 mm
distance D = 2.20 m
solution
we know that this is double slit experiment
so we apply here Fringe width formula that is
β = 
....................1
is Wavelength of light and D is Distance between screen and slit and d is slit width
so put here value and we get
= 
= 437.27 × 
m
wavelength = 437.27 nm
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:
Answer D: It describes the relationship between motion and force.
Explanation:
The answer is D because a law is something that describes something in nature, but does not try to explain how or why is occurs (that is a theory). Options B and C sound more like theories, while option A sounds like a definition. Option D is correct because a law describes without explaining.
