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What is average kinetic energy?

What is the Kinetic Energy and Gravitational Potential Energy?

  • The 4.00 kg cannon ball is again taken to the top of the other building and held 40.0 m above the ground. This time it is tossed downward with a speed of 8.00 m/s. Using energy conservation and assuming negligible air resistance, calculate its a) kinetic energy, b) gravitational potential energy, and c) speed when it has fallen 30.0 m. Show all work. 1. kinetic energy 2. gravitational potential energy 3. speed - I know this is 25.5 m/s

  • Answer:

    Kinetic energy = 1/2 mv^2 so plug in your numbers & you should get the right answer, I can't remember the formula for GPE but if I remember right it has m & h/y (height, y axis) & just plug in #'s for that one too. Hope this helps, it's been awhile!

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Kinetic energy = 1/2 mv^2 so plug in your numbers & you should get the right answer, I can't remember the formula for GPE but if I remember right it has m & h/y (height, y axis) & just plug in #'s for that one too. Hope this helps, it's been awhile!

Kelly M

Kinetic energy = 1/2 x M x V^2 1.) 0.5 x 4kg x 8^2 = 128J 2.) GPE = Energy contained in an object that is defying gravity, when an object is raised or lifted it gains GPE. to work out GPE you use the formula: M x G x H. Where M = Mass. G = Gravity due to acceleration (9.81m/s^2) and H = 40m. GPE = 4kg x 9.81 x 40m = 1569.6J 3.) Speed when it has fallen 30m. Remember that as something falls it loses it's stored GPE, and as it loses the GPE it gains Kinetic energy. Hold up a ball, you store GPE in the ball...release the ball and as it falls, it converts that GPE into Kinetic energy. When it reaches the point where it's just above the ground, it's GPE would be 0. And it's Kinetic energy would be equal to it's earlier GPE value. Hence After a fall, mgh = 1/2 x MV^2. So...Kinetic energy at 30m = mgh. where h = 30m. 4*9.81*30 = 1177.2J 1/2 x m x v^2 = 1177.2J 0.5 x 4 x v^2 = 1177.2J 2 x v^2 = 1177.2J v^2 = (1177.2/2)J v^2 = 588.6J v = 24.2610799 m/s v = 24.3 m/s.

JJ X

Kinetic energy = 1/2 x M x V^2 1.) 0.5 x 4kg x 8^2 = 128J 2.) GPE = Energy contained in an object that is defying gravity, when an object is raised or lifted it gains GPE. to work out GPE you use the formula: M x G x H. Where M = Mass. G = Gravity due to acceleration (9.81m/s^2) and H = 40m. GPE = 4kg x 9.81 x 40m = 1569.6J 3.) Speed when it has fallen 30m. Remember that as something falls it loses it's stored GPE, and as it loses the GPE it gains Kinetic energy. Hold up a ball, you store GPE in the ball...release the ball and as it falls, it converts that GPE into Kinetic energy. When it reaches the point where it's just above the ground, it's GPE would be 0. And it's Kinetic energy would be equal to it's earlier GPE value. Hence After a fall, mgh = 1/2 x MV^2. So...Kinetic energy at 30m = mgh. where h = 30m. 4*9.81*30 = 1177.2J 1/2 x m x v^2 = 1177.2J 0.5 x 4 x v^2 = 1177.2J 2 x v^2 = 1177.2J v^2 = (1177.2/2)J v^2 = 588.6J v = 24.2610799 m/s v = 24.3 m/s.

JJ X

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