in the figure shown, if the mass of the block is 4kg and the coefficient of static friction is 0.5 and the coefficient of kinetic friction is 0.3 what is the minimum force F needed to move the block

Ff = 19.6 N

Explanation:

So since its saying whats the minimum F to move the block, we will use static friction (0.5).

We will use the equation for force of friction, which is Ff = uFn

Ff = (0.5) (4) (9.8)

Ff = 19.6 N

this is the minumum force needed to move the block, as that is the frictional force. You would need to apply a minimum force of 19.6 N to move the block