The weight of an object is the force acting on the object's mass due to gravity. The weight of an object can be practically measured using a newtonmeter, which is a spring balance.
Scientists write this type of relationship in a short form as:
Weight can be calculated using the equation:
weight = mass × gravitational field strength
This is when:
The Moon is smaller and has less mass than the Earth, so its gravitational field strength is only about one-sixth of the Earth's. For example, a 120 kg astronaut weighs 1,200 N on Earth but only 200 N on the Moon. Remember that the mass would still be 120 kg.
An apple has a mass of 100 g. Calculate its weight on Earth ( = 9.8 N/kg).
100 g = 100 ÷ 1000 = 0.1 kg
= 0.1 kg × 9.8 N/kg
= 0.98 N
Calculate the weight of a 30 kg dog ( = 9.8 N/kg).
= 30 kg × 9.8 N/kg
= 294 N