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A 1400-kg car is moving at a speed of 25 m/s. How much kinetic energy does the car have?

Guest May 3, 2017
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 #1
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When the car is at the crest of the hill and moving at uniform speed there are two forces acting on it. One is the vertically downward force (f1) due to gravity, and a vertically upward force (f2) due to centrifugal force movement of the car along the circular path over the hill.

We calculate the downward gravitational force using the formula:

f1 = m*g = 1400*9.81 = 13734 N

Similarly, we calculate the upward centrifugal force using the formula:

f2 = m*(v^2)/r = 1400*(25^2)/210 = 4166.6667 N

The net force acting on the car is:

= f1 - f2 = 13734 - 4166.6667 = 9567.3333 N downward

Answer:

Applied force on the car is 9567.3333 N downward.

Gwendolynkristine  May 3, 2017
 #2
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KE = 1/2 x M x V^2, where M =Mass, V =Velocity

KE = 1/2 x 1,400 x 25^2

KE = 1/2 x 1,400 x 625

KE = 437,500 Joules.

Guest May 3, 2017

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