IIT JEE Physics (1978-2018: 41 Years) Topic-wise Complete Solutions

# How Much is One Newton?

## Introduction

Newton is the SI unit of force. Though we use this unit from class 8 onwards and spends years after year with this, a feel of how strong a newton is, is not developed. This experiment is designed to develop a feeling of 1 N force.

## Apparatus

Spring action based weighing machine

## Procedure

1. Take a weighing machine where the object is placed on the platform and the mass in displayed on a dial. See the reading, if it has any zero error, correct it.
2. Ask a student to press the pan of the weighing machine by a force which he thinks is 1 N. To dramatise, ask the student not to see the reading and push the platform. Some other student should read the reading and tell how many newton of force the first student has applied.
3. Finally let the student see the reading and adjust the push till the dial reading shows 100 gram. Repeat for other magnitudes of force such as 5 N, 10 N etc.

## Discussion

If 100 gram mass is put on the platform, it presses the platform by a force $$mg=0.1\times9.8\approx 1\,\mathrm{N}$$. The idea is to press the platform with a force which gives 100 gram reading. This force will be 1 Newton.

## Questions

What is the maximum force you can push a weighing balance kept on the ground?