Force and acceleration
A body with a mass of 1.0 kg is accelerated by a force F = 2.0 N. What is velocity of this body after 5.0 s of motion?
Note. We use “bold face” notation of vector quantities here.
Solution.
Given:
m = 1.0 kg – mass of the body,
F = 2.0 N – force acting on the body
t = 5.0 s – time of motion of this body.
From Newton’s Second Law of Motion
F = m a (1)
we get expression for acceleration
a = F/m (2)
Velocity, according to general formula
v = v0 + a t (3)
where v0 = 0, and acceleration is given by equation (2), will be
v = (F/m)t (4)
Substituting numbers given in the problem we get
In the last line we used an arrow to indicate a vector quantity. It is a lack of consequence, but we would like the Reader to get familiar with both methods of writing vectors.
The algebra leading to the final units was presented with all possible details. Later on we will omit such very elementary algebraic “transformation”.