The drawing shows a large cube (mass = 22 kg) being accelerated across a horizontal frictionless surface by a horizontal force P. A small cube (mass = 2.8 kg) is in contact with the front surface of the large cube and will slide downward unless P is sufficiently large. The coefficient of static friction between the cubes is 0.71. What is the smallest magnitude that P can have in order to keep the small cube from sliding downward?
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2007-10-09 13:00:31 · 1 answers · asked by Marianna E 1 in Science & Mathematics ➔ Physics
If the small block is to stay fixed to the big cube, the force that the big cube pushes against the small cube (The normal force) must be such that:
f = uN = mg where N= normal force, u = coefficient of static friction, m = mass of small block and g = acceleration due to gravity.
Now N = P since P is the force being applied to the large block in the horizontal direction. So,
uP = mg ---> P = mg/u = 2.8 *9.8/.71 = 38.65 Nt
2007-10-09 13:08:59 · answer #1 · answered by nyphdinmd 7 · 0⤊ 1⤋