Suppose you hoist a 100kg crate straight UP with a force of 1,500N. What is the acceleration of the crate?
F = ma or a = F/m = 1500/100 = 15 m/s? BUT, if this is on or near the surface of the earth, then we have to take the weight of the crate into account. Weight = mg = 980 newtons. Net force is the difference 1500–980 = 520 newtons and acceleration is F/m = 520/100 = 5.2 m/s?
