a car if nass 1600kg coast down a 10 percent grade from A to B, a distance of 30m and then coast along a level road until it stops at C. assume the road resistance to remain constant of 200N for the entire distance A to C, if the initial velocity of the car at A is 25kph, compute:
a.) its velocity at B
b.) the distance s it coast from B to C.
Motion from A to B
$\left[ \frac{1}{2}(1600)\left( \dfrac{25}{3.6} \right)^2 + 1600(9.81) \left( \dfrac{30}{\sqrt{101}} \right) \right] - 200(30) = E_B$
$E_B = 79,434.56 ~ \text{N}\cdot\text{m}$
$\frac{1}{2}(1600)\left( \dfrac{v_B}{3.6} \right)^2 = 79,434.56$
$v_B = 35.87 ~ \text{kph}$
Motion from B to C
$79,434.56 - 200s_{BC} = 0$
$s_{BC} = 397.17 ~ \text{m}$
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