Answer:
Explanation:
Let's answer these statements
.1) True. This is the law of reflection.
.2) False. The speed of light depends on the index of refraction n = c / v
v = c / n
.3) True. The frequency creates a forced oscillation, whereby the atoms re-emit at the same incident frequency
.4) False. The index of refraction is a measure of the ratio of the speed of light in a vacuum and the material environment, the ability to change the trajectory is given by the law of refraction
.5) True. True due to the change in beam trajectory due to the law of refraction
.6 False. The phenomenon occurs when you pass from a medium with a higher index to one with a lower ratio, because the refracted beam separates from the normal
.7) True.
.8) False so that the lightning approach is valid Lam >> d,
.9) True.
Have everything in control and in order and discuss about different issues.
Answer:
29223.6J
Explanation:
Given parameters:
Mass of Piano = 852kg
Height of lifting = 3.5m
Unknown:
Gravitational potential energy = ?
Solution:
The gravitational potential energy of a body can be expressed as the energy due to the position of a body;
G.P.E = mgh
m is the mass
g is the acceleration due to gravity
h is the height
Now insert the given parameters and solve;
G.P.E = 852 x 9.8 x 3.5 = 29223.6J
For conservation of energy we have to:
mgH=mv²/2
Clearing
<span> v=sqrt(2gH)
Then, by definition
</span><span> F=Δp/Δt= Δ(mv)/ Δt=m Δ(v)/Δt=
</span> =m[sqrt(2gH)-0]/Δt= m[sqrt(2gH)]/ Δt
the answer is
F=m[sqrt(2gH)]/ Δt
