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# Measuring Weight

### Measuring Weight

There is a subtle difference between calculating weight and mass which you will find out in this lesson. Weight can be measured using a certain instrument, and is useful to make comparisons.

Jamie and Claire are in a discussion about weight and mass. Jamie thinks they are the same thing whilst Claire is certain they are different. Who is correct?

Which of the following do we measure in Kilograms (Kg)?

Which of the following do we measure in Newtons?

Which of the following could we measure with a Newton-Metre?

To sum up, due to the fact that weight is a force **** (remember **** $weight=mass\times gravity$) , we can measure weight using a **Newton-metre**. This is also sometimes known as a **spring-balance** due to the fact it involves the **** tension on a spring.

This image shows how a Newton-metre works.

You can see the spring with a scale to show you readings.

What do you think the readings show?

What is the force which causes this weight?

What is the weight of this apple?

If the weight is 2 Newtons, what would the mass be (in Kg) if gravity on Earth is 10N/Kg?

If we wanted to work out the mass and weight of an object and compare them, which would be a suitable piece of equipment to use? Select all appropriate answers from the list below.

You can select multiple answers

If an object is weighed on a balance and has a weight of 100 Newtons on Earth, then what will be the mass of the object in Kilograms (Kg)?

Which of the objects, **A** or **B**, has the greatest weight?

Which object, A or B, has the greater mass?

To sum up we can use balances to **compare weights** by seeing which exerts the greatest force and therefore ends closer to the ground. This is used in shops to measure the weight of objects when you are charged by weight, for example in a greengrocers.