The intensity is defined as the ratio between the power emitted by the source and the area through which the power is calculated:
(1)
where
P is the power
A is the area
In our problem, the intensity is
. At a distance of r=6.0 m from the source, the area intercepted by the radiation (which propagates in all directions) is equal to the area of a sphere of radius r, so:
And so if we re-arrange (1) we find the power emitted by the source:
Answer:
B) Friction
Explanation:
The main source of error is the omission of the effect from friction between block and incline, which is directly proportional to the mass of the block. The force of gravity is constant. The friction force dissipates part of the gravitational potential energy, generating a final speed less than calculated under the consideration of a conservative system. Air resistance is neglected at low speeds like this case.
Answer:
Yes
Explanation:
p = momentum of photon
E = energy of photon
c = velocity of light
Units of p = kg m /s
Units of E = kg m^2 / s^2
Units of E / p = {kg m^2 / s^2} / {kg m /s} = m/s
It is the unit of speed, so by the division of energy to the momentum, we get the speed. yes it is correct.
The average speed would have to be 260 km/hr due to the driver originally going 30 km/hr too slow the first two laps
