Ablock of mass 5 kg is placed on a rough table having a coefficient of static friction μs = 0.2.what is the force required to move the block?

We need to (at least) apply a force of 9.8 N to move the block

Explanation:

Second Newton's Law

If a net force different from zero is applied to an object of mass m, then it will move at an acceleration a, given by

If we apply a force F to an object placed on a rough surface, the only way to make it move is to beat the friction force  which is given by

Where is the static friction coefficient and is the normal force exerted by the table to the object. Since there is no motion in the vertical direction the normal force equals the weight of the object:

The friction force is

Thus, we need to (at least) apply a force of 9.8 N to move the block

vapour or gas assuming atmospheriv pressure

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