Answer:
Ff = 19.6 N
Step-by-step 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