Question

Two soccer players kick the same 1-kg ball at the same time in opposite directions. one kicks with a force of 20 n; the other kicks with a force of 12 n. what is the resulting acceleration of the ball, in m/s2.

Answer 1

We can solve the problem by using Newton's second law of motion:
$\sum F = ma$ (1)
where
the term on the left is the resultant of the forces acting on an object
m is the mass of the object
a is the acceleration of the object

The mass of the ball in this problem is m=1 kg. Two forces are applied, in opposite directions, of 20 N and 12 N, therefore the resultant of the forces is
$\sum F= 20 N-12 N=8 N$

Therefore, we can rearrange eq.(1) and use these data to find the acceleration of the ball:
$a= \frac{\sum F}{m}= \frac{8 N}{1 kg}=8 m/s^2$