Question 4
An object weighs 49 N. What is its mass? (Take g = 9.8 m s−2.)
The right answer is the one marked above.
5 kg. Use weight = m g in reverse to find the mass:
m = weight ÷ g = 49 N ÷ 9.8 m s−2 = 5 kg
Check it: 5 kg × 9.8 m s−2 = 49 N. ✓
480 kg comes from multiplying instead of dividing. Since g is greater than 1, a weight is always a bigger number than its mass — so finding the mass means dividing.