D = 1/f, where D is the power in diopters and f is the focal length in meters.
D=1/20
<u>D=0.05</u>
Answer:
The height at which the object is moved is 10 meters.
Explanation:
Given that,
Force acting on the object, W = F = 490 N
The gravitational potential energy, P = 4900 J
We need to find the height at which the object is moved. We know that the gravitational potential energy is possessed due to its position. It is given by :

So, the height at which the object is moved is 10 meters. Hence, this is the required solution.
Work = force * distance.
We must produce twice as much energy as we are lifting the weight twice as high.
But we are not increasing the force so we must increase the length of the ramp ( distance ) instead.
The new length will be twice as great as the previous length.
So 8 metres is required.
25 kg * 8 m = work = 100 kg * 2 m
Your answer is correct. No problem and Have a nice day