Question

A grapefruit has a weight on earth of 4.9 newtons. What is the grapefruit's mass?

Answer 1

Weight = mg where m = mass and g = gravity = 10 (9.81....)
so m = w/g = 4.9 / 10(9.81....) = 0.49 (0.49949....)
if you get given g as 10, answer is 0.49 kg 
if you get given g as 9.81, answer is 0.50 (1sf)

Answer 2

Answer:

The grapefruit's mass is 0.5 kg.

Explanation:

Given that,

Weight = 4.9 N

We need to calculate the mass

Using formula of newton's second law

$F = mg$

$m = \dfrac{F}{g}$

Where, F = weight on earth

g = acceleration due to gravity

Put the value into the formula

$m = \dfrac{4.9}{9.8}$

$m =0.5\ kg$

Hence, The grapefruit's mass is 0.5 kg.