What is weight?
The pull of the Earth, in newton.
Hanging from a spring
You hang different objects from a spring. The spring stretches by different amounts.
What pulls the objects down and stretches the spring?
What this lesson covers
The idea
The weight of an object is the force with which the Earth pulls it towards itself; being a force, it is measured in newton (N), and different objects have different weights.
Hanging from a spring
You hang different objects from a spring. The spring stretches by different amounts.
What pulls the objects down and stretches the spring?
- The Earth
- The spring itself
- The air
Hang the bags
Hang each bag on the spring. Read the pointer.
The Earth pulls
The Earth pulled each bag down. The bags stretched the spring by different amounts, so their weights are different. Weight is a force, so it is measured in newton.
The force with which the Earth pulls an object towards itself is the weight of the object. Weight is a force, so its SI unit is the newton (N). Different objects have different weights.
- Object | Weight
- Small bag | 10 N
- Medium bag | 20 N
- Large bag | 30 N
Notes
The weight of an object is the force with which the Earth pulls it. It is measured in newton (N). Different objects have different weights.
Check yourself
The weight of an object is the force with which …
What is the SI unit of weight?
Weight is a force. So it is measured in the same unit as …
Do different objects have the same weight?
- the Earth pulls it towards itself — correct. Yes!
- the object pulls the Earth away. Weight is the pull of the Earth on the object.
- a magnet pulls it. Weight is the pull of the Earth, not of a magnet.
- The kilogram (kg). The kilogram is a unit of mass. Weight is a force, measured in newton.
- The newton (N) — correct. Yes!
- The metre (m). The metre is a unit of length.
- length. Length is measured in metres. Weight is a force.
- time. Time is measured in seconds. Weight is a force.
- force — correct. Yes!
- No, different objects have different weights — correct. Yes!
- Yes, all have the same weight. The spring stretched by different amounts, so the weights differ.
- Yes, if they are the same colour. Colour does not decide it. The spring stretched differently for different objects.