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A 2.0 x 103 kg car is pulled 345 m up a hill that make s an angle of 15 with the horizontal....

Question:

A 2.0 x 103 kg car is pulled 345 m up a hill that makes an angle of 15 with the horizontal.

a. What is the potential energy of the car at the top of the hill?

b. If the car rolls down the hill, what will its speed be if we neglect friction?

Conservation of Energy:

Conservation of energy states that the energy of the system is equal to the energy of the system after a reaction has happened. For a car moving down a hill without friction, the car's kinetic energy will only be converted to potential energy making the total energy conserved.

Answer and Explanation:

(A) Using the equation for the potential energy, we write:

{eq}U = mgh \\ U = (2.0\times10^3)(9.8)(345\sin{15}) \\ U = 1.75\times10^6 \ J {/eq}

(B) In this case, all the potential energy will be converted to kinetic energy. We write:

{eq}\frac{1}{2}(2000)v^2 = 1.75\times10^6 \\ v =41.8 \ m/s {/eq}


Learn more about this topic:

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Energy Conservation and Energy Efficiency: Examples and Differences

from Geography 101: Human & Cultural Geography

Chapter 13 / Lesson 9
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