Question

the force of gravity acting
on a child's mass on earth is 490 newtons. what's the child's mass?

Answer 1

F = m • a

What we know:
- Gravity: 9.8 m/s
- Force: 490 N

Equation derived:
m = F/a
m = 490/9.8
= 50 kg

Answer 2

50 kg because e = mc2