2 What factors affect the size of friction? 1. Look at the pictures on page 57. Imagine Fred is pulling a very heavy object. Will the friction acting on the object increase so that it is harder for him to pull the object? 2. Use a spring balance to pull a wooden block with different weights. Find out how the size of friction is different.
Activity Booklet 30
lift ring
The larger the pulling force acting on the spring balance, the longer the spring stretches and the greater the reading. When we use a spring balance, we should: (1) lift the spring balance vertically
spring
pointer
scale plate
and check whether the pointer is pointing at ‘0’. If not, move the scale plate and adjust the pointer until it points at ‘0’.
hook
‘N’ is the unit of force.
(2) place the pointer at eye level when we read the reading.
(3) keep the force we want to test below the maximum reading on the scale of the spring balance.
Quick Check The heavier the object, the greater / smaller the friction it creates when it moves on a surface.
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