Physics Unit 2.1: Mass and Weight

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Unit 2.1 Mass and Weight

1. Be able to distinguish between the mass and weight of an object.

Mass = the amount of substance in an object; measured in g/kg

Weight = a force due to gravity; measured in Newtons N

2. Demonstrate understanding that mass is a property that ‘resists’ change in motion.

If a force is applied to an object, it does not immediately reach a high speed as it takes time for it to accelerate. If the force is constant, there won't be constant acceleration. If the force is not constant, there will be a moment of acceleration, allowing the object to accelerate. 

For example, you hit a ball. You are the force that moves the ball, and it takes time for the ball to accelerate in the air. If you keep contact with the ball, it stays at a constant speed and will not move faster. If you hit it and lose contact, the ball will fly up into the air and accelerate. 

3. Know that the Earth is the source of a gravitational field. 

Anything with a mass will be pulled down to Earth by the force of weight. If the object has a big mass, a bigger force will be applied to it.

4. Describe, and use the concept of, weight as the effect of a gravitational field on a mass.

In comes the equation for weight:

weight = mass x gravity

N = g x m/s^2