An object with a mass of 5 kg is on a surface with a kinetic friction coefficient of  4 . How much force is necessary to accelerate the object horizontally at  12 m/s^2?

Force F=64Newtons.

Explanation:

This case is taken as Motion of block on a rough fixed horizontal surface.
In this case, if the block slides or moves with an acceleration under the influence of an external force 'F', the acceleration of the block is
$a = \left(F - {f}_{\text{k}}\right) / m$
$\implies F = m a + {f}_{\text{k}}$
Now substituting the values we get
F = (5)(12) + 4
$\therefore F = 64 N$