For the work-energy theorem, the work needed to stop the bus is equal to its variation of kinetic energy:
where
W is the work
Kf is the final kinetic energy of the bus
Ki is the initial kinetic energy of the bus
Since the bus comes at rest, its final kinetic energy is zero:
, so the work done by the brakes to stop the bus is
And the work done is negative, because the force applied by the brake is in the opposite direction to that of the bus motion.
a.
The work done by a constant force along a rectilinear motion when the force and the displacement vector are not colinear is given by:
where F is the magnitude of the force, theta is the angle between them and d is the distance.
The problen gives the following data:
The magnitude of the force 750 N.
The angle between the force and the displacement which is 25°
The distance, 26 m.
Plugging this in the formula we have:
Therefore the work done is 17673 J.
b)
The power is given by:
the problem states that the time it takes is 6 s. Then:
Therefore the power is 2945.5 W
Answer:D. λfilm/4
Explanation: Destructive interference is a type of wave interference which means the coming together or over-lapping of two opposing waves creating No effect or the Cancellation of the wave impact. An example of destructive wave is when Noise cancel the effect of sound from a head phone.
The film thickness will need to be increased by λfilm/4 for it to be able to give a destructive interference.
Because the Moon has a very small surface area compared to other spacial geo-bodies, it has cooled down much faster than Earth. Any water on the moon would freeze.
Answer:
14523.55J
Explanation:
The work done by the jogger against gravity is given by the following equation;
where m is the mass, g is acceleration due to gravity taken as 
and h is the height of the hill.
Since the length of the hill is 132m and it is inclined at 12 degrees to the horizontal, the height is thus given as follows;
Substituting this into equation (1) with all other necessary parameters, we obtain the following;
