physics

just a couple more questions

1.) The power needed to accelerate a projectile from rest to is launch speed v in a time t is 43.0 W. How much power is needed to accelerate the same projectile from rest to launch speed of 2v in a time of 1/2t?

2.)A ball is fixed to the end of a string , which is attached to the eiling at point P, which is at the top. the ball is positioned below it, what enables it to go back to point P? Hope this makes sense. Like swinging the ball basically

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  1. 1) You need to produce four times the kinetic energy (because of the V^2 dependence) in half the time. What does that tell you about the power required?

    2) When the ball is below what? It cannot return to the ceiling from below unless it is given sufficient kinetic energy.

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  2. The velocity would be four times as great and the time would be two times as great. So the power would be (43)(4)(2)=344 watts

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  3. Well you see the coefficient of friction is zero and the air resistance is too strong thus the projectile would go the speed of light and end the entire human race as we know it would come to an end. It would be better to not accelerate that object. Dinosaurs extinction is based on the theory of this problem. Once the velocaraptor figured out how fast it would take he killed them all off

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