A box of mass m is released from rest at posi | vedclass

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(D) The correct answer is $mgh = \frac{1}{2}mv^2$. This equation is an application of the law of conservation of mechanical energy. In this situation,

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$mgh = (1/2)mv^2$

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(D) The correct answer is $mgh = \frac{1}{2}mv^2$. This equation is an application of the law of conservation of mechanical energy. In this situation,the loss in potential energy,$mgh$,is equal to the gain in kinetic energy,$\frac{1}{2}mv^2$.The other equations are kinematic equations that are only valid when the acceleration is constant. Since the track is curved,the component of the gravitational force on the box that is tangent to the track surface changes as the box slides. This component of the gravitational force is what accelerates the box. According to Newton's second law,$F = ma$,as the force changes,the acceleration also changes. Since the acceleration is not constant,the other equations are not valid.

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