Answer:
the angle of incidence equals the angle of reflection
The formula for work is N x m, which will equal in joules.
500 x 5 = 2,500 joules
Answer:
A) Must be done 19806.62 joules of work.
B) The average power is 1320.44 Watts.
Explanation:
A) First, we're going to use the work-energy theorem that states total work (
) done on an object is equal to the change in its kinetic energy (
):
(1)
So, all we must do is to find the change on kinetic energy. Because we're working with rotational body, we should use the equation 
for the kinetic energy so:
(2)
with 
the initial angular velocity, 
the final angular velocity (is zero because the wheel stops) and I the moment of inertia that for a thin hoop is 
, using those on (2)
(3)
By (3) on (1):
B) Average power is work done divided by the time interval:
NOTE: We use the relation 
to convert 280 rev/min(rpm) to 29.32 rad/s
Actually, they're not. There's a group of stars and constellations arranged
around the pole of the sky that's visible at any time of any dark, clear night,
all year around. And any star or constellation in the rest of the sky is visible
for roughly 11 out of every 12 months ... at SOME time of the night.
Constellations appear to change drastically from one season to the next,
and even from one month to the next, only if you do your stargazing around
the same time every night.
Why does the night sky change at various times of the year ? Here's how to
think about it:
The Earth spins once a day. You spin along with the Earth, and your clock is
built to follow the sun . "Noon" is the time when the sun is directly over your
head, and "Midnight" is the time when the sun is directly beneath your feet.
Let's say that you go out and look at the stars tonight at midnight, when you're
facing directly away from the sun.
In 6 months from now, when you and the Earth are halfway around on the other
side of the sun, where are those same stars ? Now they're straight in the
direction of the sun. So they're directly overhead at Noon, not at Midnight.
THAT's why stars and constellations appear to be in a different part of the sky,
at the same time of night on different dates.
You have to have electrons that are in the materials conduction band. Then you apply a voltage across the material.
