friction force up slope = .27 * m * 9.81 * cos 25
= 2.40 m
gravity component down slope
= m * 9.81 * sin 25
= 4.15 m
net force down slope = 4.15m -2.40m
= 1.75 m Newtons
Now you can do the problem
F = m a = 1.75 m
so
a = 1.75 m/s^2 down plank
3 = (1/2) a t^2
6 /1.75 = t^2
t = 1.85 seconds
V = a t = 1.75 * 1.85
1. A box is placed on the end of a 3 meter plank. One end of the plank is gradually raised and it is observed that the box begins to slide when the board reaches an angle of 25 degrees.
a. Determine how long the box will take to reach the end of the plank if the coefficient of kinetic friction between the box and the plank is 0.27.
b. What is the velocity of the box at the bottom of the incline.
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