Answer:
The speed of Susan is 2.37 m/s
Explanation:
To visualize better this problem, we need to draw a free body diagram.
the work is defined as:
here we have the work done by Paul and the friction force, so:
Now the change of energy is:
Answer:
1. telescope
2.
f- focal length
f- focal length r- the radius of curvature of the mirror
p-the distance of the object from the vertex of the mirror
l-the distance of the figure from the vertex of the mirror
Answer:
The SI unit of intensity is the watt per square meter/metre (W/m^2.)
Explanation:
Intensity is equal to the power transferred per unit area. Since power is measured in watts (W) and 1 W = 1 J/s, then intensity can be viewed as how fast energy goes through a certain area.
In physics, intensity is often used when studying light, sound, or other phenomena that involve waves or energy transfer. (With waves, the power value is taken as the average power transfer over the wave's period.)
Answer:
500 watts
Explanation:
Recall that the definition of power is the amount of energy delivered per unit of time.
In our case, the energy delivered is potential energy which we can estimate as the product of the weight of the object times the distance it is lifted above ground:
200 N x 10 m = 2000 Nm
then the power is the quotient of this potential energy divided the time it took to lift the object to that position:
Power = 2000 / 4 Nm/s = 500 Nm/s = 500 watts
