Resistance, magnetism, upthrust Can you write the following words five times in the back of your books. Resistance, magnetism, upthrust Do now! He’s going to blow! Be careful Good Neutral Excellent MOODOMETER
Today’s lesson What is a force? Contact and non-contact forces Units of force Measuring forces
What is a force? A force is a push (or a pull)
What is a force? A force can change the shape of an object
What is a force? A force may also change the speed and direction of an object
Contact forces Many forces need contact to affect an object
Non-contact forces Some forces can affect an object from a distance
Forces are measured in units called NEWTONS. Measuring force We can measure a force with a forcemeter Forces are measured in units called NEWTONS.
The force of gravity pulling on an apple is about 1 N Measuring forces The force of gravity pulling on an apple is about 1 N 1 N
The force needed to pull a truck is about 3000 N Measuring forces The force needed to pull a truck is about 3000 N 3000 N
Let’s measure some forces! Can you stick the sheet in?
Today’s lesson Upthrust Measuring upthrust Floating and sinking
Upthrust Gently lower a mass on a Newton meter into a beaker of water. Sketch a diagram in your book and write a sentence describing what happens.
What happens if the upthrust is equal to the force of gravity?
What happens if the upthrust is equal to the force of gravity?
Which is heavier? 5 kg 5 kg
Density 5 kg 5 kg
Density Density is the mass of one cubic centimetre of a substance. So for example, gold has a density of 19.3 g/cm3. This means one cubic centimetre (cm3) of gold has a mass of 19.3 grams.
The formula! Density = mass volume Or using the formula triangle; m g/cm3 g Density = mass volume Or using the formula triangle; m D x V cm3
Density of regular shapes volume = length x width x height density = mass/volume mass using a scale height width length
Now let’s measure some densities.