1) Star from the definition of power:
P = work/ time = W / Δt
We know that work is given by force times displacement:
W = F · Δd
Substituting in our formula:
P = F · Δd / <span>Δt
But we know by definition that </span>Δd / <span>Δt = velocity, therefore we can write:
</span>P = F · v
which is the alternative formula saying that Power is equal to Force times Velocity
2) No, it is not a violation of the Law of conservation of energy because as the spring slows down, the kinetic energy is transformed into potential energy and their sum stays constant.
After 5 seconds the stone will have fallen 49 m
Answer:
Explanation:
Momentum is the mass of a moving body times its velocity. It can be transferred from one object to another
So since m is on both sides of the equal sign, they cancel each other out. Then multiply both sides by 2, so you get 2gh = v². Then (I'm assuming) g = acceleration due to gravity = 9.80 m/s². If you multiply it by the two, you get 19.6 m/s². I'm assuming h is the height, in meters. If you have the number for h, plug it in now and multiply that. You'll get some number x that has a value of m²/s². Since you're looking for v, and right now you only have v², take the square root of both sides of your equation and that'll give you the answer. If you don't have a value for h, though, just write your answer like √(2gh) = v or whatever format like that your teacher usually wants, and you should be good. I don't know how far the teacher wants you to simplify or solve this, but hopefully this gives you what you need! :)