A crate, with a mass of 25 kg, slides down a plane which is inclined at 15º to the
horizontal. During the first part of the motion, from A to B, there is no friction between
the crate and the plane, but part BC has a rough surface.
5.1 Draw a free-body diagram of ALL the forces acting on the crate while it moves
from B to C. (3)
5.2 Calculate the magnitude of the acceleration of the crate while it moves from A
to B. (4)
5.3 Write down the direction of the acceleration of the crate while it slows down
from B to C. Write only UP THE SLOPE or DOWN THE SLOPE. (1)
5.4 The magnitude of the net acceleration from B to C is 1,2 m·s-2.
Calculate the magnitude of the frictional force acting on the crate. (4)
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