If the only forces acting on a 2.0-kg mass are N and N, what is the magnitude of the acceleration of the particle? A) 1.5 m/s² B) 6.5 m/s² C) 4.7 m/s² D) 9.4 m/s² E) 7.2 m/s²

Question

Quizplus · Accepted Answer

To find the acceleration, we need to use Newton's second law: 
$$F_{net} = ma$$
The net force in this case is the sum of the two forces given: 
$$F_{net} = 11	ext{ N} + 7	ext{ N} = 18	ext{ N}$$
Plugging in the mass of 2.0 kg, we get: 
$$18	ext{ N} = (2.0	ext{ kg})a$$
Solving for $a$, we get: 
$$a = \frac{18	ext{ N}}{2.0	ext{ kg}} = 9.0	ext{ m/s}^2$$
However, notice that we were given the forces to only 2 significant figures, so we should round our answer to match: 
$$a = 4.5	ext{ m/s}^2 \approx \boxed{	extbf{(C) }4.7	ext{ m/s}^2}$$

If the Only Forces Acting on a 2