The one that does that is the photoelectric effect. This allows the sun to hit the surface and produces enough energy for electrons to be knocked off the atom and allows a current to move.
Answer:

Explanation:
Given that,
The radius of a bend, r = 20 m
Velocity of motorcyclist, v = 3 m/s
The combined mass of motorcyclist and the motorcycle is 50 kg
We need to find the motorcyclist’s centripetal acceleration. The formula used to find the centripetal acceleration is given by :

So, the acceleration of the motorcyclist is
.
Given,
Radius of curvature of concave mirror = 1.6m
We know that ,
Focal length = radius/2
Hence ,
Focal length of concave mirror = radius of concave mirror /2
=> F = 1.6/2
=> F = 0.8m
Hence the focal length of concave mirror is 0.8 m
We have that F=ma from the 2nd Newton law where F is the force, m is the mass and a is the acceleration. Suppose we have that F' is the new force and m' is the new mass. Then, we have that a'=F'/m' still, by rearranging Newton's law. We are given that F'=2F and m'=m/2. Hence,

But now, we have from F=ma, that a=F/m and we are given that a=1m/s^2.
We can substitute thus, a'=4a=4*1m/s^2=4m/s^2.
Answer:
12500W
Explanation:
Given parameters:
Work done = 250000J
Time taken = 20s
Unknown:
Power of the crane = ?
Solution:
Power is the defined as the rate at which work is being done;
Mathematically;
Power =
insert the parameters and solve;
Power =
= 12500W