Answer:
29.2 ft/s
Explanation:
The distance of the light's projection on the wall
y = 13 tan θ
where θ is the light's angle from perpendicular to the wall.
The light completes one rotation every 3 seconds, that is, 2π in 3 seconds,
Angular speed = w = (2π/3)
w = (θ/t)
θ = wt = (2πt/3)
(dθ/dt) = (2π/3)
y = 13 tan θ
(dy/dt) = 13 sec² θ (dθ/dt)
(dy/dt) = 13 sec² θ (2π/3)
(dy/dt) = (26π/3) sec² θ
when θ = 15°
(dy/dt) = (26π/3) sec² (15°)
(dy/dt) = 29.2 ft/s
Answer:
<em>d. The sail should be reflective because in this case the momentum transferred to the sail per unit area per unit time is larger than for absorbing sail, therefore the radiation pressure is larger for the reflective sail.</em>
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Explanation:
Let us take the momentum of a photon unit as u
we know that the rate of change of momentum is proportional to the force exerted.
For a absorbing surface, the photon is absorbed, therefore the final momentum is zero. From this we can say that
F = (u - 0)/t = u/t
for a unit time, the force is proportional to the momentum of the wave due to its energy density. Therefore,
F = u
For a reflecting surface, the momentum of the wave strikes the sail and changes direction. Since we know that the speed of light does not change, then the force is proportional to
F = (u - (-u))/t = 2u/t
just as the we did above, it becomes
F = 2u.
From this we can see that the force for a reflective sail is twice of that for an absorbing sail, and we know that the pressure is proportional to the force for a given area. From these, we conclude that <em>the sail should be reflective because in this case the momentum transferred to the sail per unit area per unit time is larger than for absorbing sail, therefore the radiation pressure is larger for the reflective sail.</em>
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1. Use renewable energy sources (eg. wind, solar etc.)
2. Encourage citizens to use public transport
3. Better waste management systems (instead of burning waste, recycle etc.)
that’s all i could think of :)
The amount of energy used in the billing period is 5,400,000,000 joules.
One kWH is the amount of energy transferred in one hour, there 1 kWh is equal to
1 kWh=1*1000*(J/s)*3600 s
=3600000 J
Thus the amount of energy in joules consumed by the user for the billing period is =1500*3600000=5,400,000,000 J.
The amount of energy used in the billing period is 5,400,000,000 joules.
Answer:
As rocket mass increases, acceleration decreases.
Explanation:
From Newton's second law of motion;
F= ma
Where;
m= mass of the object
a= acceleration of the object
Hence we can write;
a= F/m
This implies that an increase in mass (m) will lead to a decrease in acceleration if the force on the object is held constant.
Hence, if the rockets have different masses, they will have different accelerations.
