Ablock of mass 3 kg, which has an initial
speed of 4 m/s at time t = 0, slides on a
horizontal surface.
find the magnitude of the work that must
be done on the block to bring it to rest. answer in units of j if a constant friction force of magnitude 2 newtons is exerted on the block by the surface, find the magnitude of the acceleration of the block.
how far does the block slide before it comes to rest? units of m

Explanation:

Kinetic energy of the block

= 1/2 m v²

= .5 x 3 x 4 x 4

= 24 J

Negative work of - 24 J is required to be done on this object to bring it to rest.

magnitude of acceleration due to frictional force

= force / mass

2 / 3

= 0 .67 m /s²

Let the body slide by distance d before coming to rest so work done by force = Kinetic energy

=  2 x d = 24

d = 12 m

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