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reaction at point A of the thin planel on a decelerating truck

In problem 16.3(a), A 60-lb uniform thin panel is placed in a truck with end A resting on a rough hoirzontal surface and end B supported by a smooth vertical surface. Knowing that the deceleration of the truck is 12 ft/s^2, determine the reactions at ends A is
a. 70.03 lb
b. 60.30 lb
c. 90.70 lb
d. 80.71 lb


Solution Preview

Let g = 9.8 m/s^2 be the free fall acceleration
Let m = (80 lb / g) be the mass of the track
a = -10 ft/s^2 = - 3.048 m/s^2 the acceleration of the truck (negative because it decelerates)
B = 30 degrees = the angle between the vertical and the panel

Let L be the length of the panel, so that the height of point B is
hb = Lcos(B) (1)
and the length of the horizontal projection of the panel is
wb = Lsin(B). (2)
We shall use these sizes for calculating the torques below.

The ...

Solution Summary

It shows how to find the reaction force at point A of the thin planel on a decelerating truck.