Around 8 hours and 20 minutes
Explanation:
I divided 500 by 60 and got 8.3333333333 and i round it up to 8.20, so it is 8 hours and 20 minutes.
A nucleus controls all the other parts of the cell
The only vertical forces are weight and normal force, and they balance since the surface is horizontal. The horizontal forces are the applied force (uppercase F) in the direction the block slides and the frictional force (lowercase f) in the opposite direction.
Apply Newton's 2nd Law in the horizontal direction:
ΣF = ma
F - f = ma
where f = µmg
F - µmg = ma
F = m(a +µg)
F = (20 kg)(1.4 m/s² + 0.28(9.8 m/s²)
F = 83 N