A 8.0-kg block is sliding down a wall with constant velocity. The coefficient of static friction between the block and the wall is μs = 0.70. The coefficient of kinetic friction between the block and the wall is μk = 0.40. What is the magnitude of the force (in N) pressing the block against the wall? Use g = 9.79 m/s2.

Question

abhisar · Answer

So, in this case the gravitational pull downwards on the box should be equal to the frictional force exerted on the box by the wall.

abhisar · Answer

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abhisar · Answer

Since, the block is moving with a constant velocity we will use coefficient of kinetic friction.

$\large \boxed{\tt Frictional~force=Normal~force\times \mu}$

Normal force here is the force by which the box is pressed against the wall.

Finally we can make an equation,

$\sf N\times \mu_k=m\times g$

Plug in the values and find the value of N.