If v is the initial speed of a vehicle, g is the gravitational acceleration, G is the upward longitudinal slope of the road and fr is the coefficient of rolling friction during braking, the braking distance (measured horizontally) for the vehicle to stop is
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$\frac{v^2}{g(G + f_r)}$
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$\frac{v^2}{2g(G + f_r)}$
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$\frac{vg}{(G + f_r)}$
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$\frac{vf_r}{(G + g)}$
B
Correct answer
Explanation
The work-energy principle states that the kinetic energy (1/2 * m * v^2) is equal to the work done by the braking force. The braking force is F = m * g * (f_r + G). Thus, 1/2 * m * v^2 = m * g * (f_r + G) * d, which simplifies to d = v^2 / (2 * g * (f_r + G)).