On a certain planet an object of mass m is moving with an initial speed of 4 m/s. It comes to rest after traveling a horizontal distance of 10 m. If the coefficient of kinetic friction between the object and the surface is 0.2, what is the value of g on that planet?

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Quizplus · Accepted Answer

The work done by friction is equal to the change in kinetic energy of the object. Therefore,$$f_kd = \frac{1}{2}mv_f^2 - \frac{1}{2}mv_i^2$$$$(0.2mg)(10) = 0 - \frac{1}{2}(m)(4)^2$$$$2mg = 8m$$$$g = 4 \ m/s^2$$

On a Certain Planet an Object of Mass M Is