Year 7 · Science · Forces · Lesson 2
Friction, air resistance, weight and mass
Friction and air resistance - useful and unhelpful effects and how to reduce them - and the difference between mass and weight, using W = m x g.
17-minute video lesson
Teaching, worked examples and 20 practice questions solved step by step.
Watch free for a monthWhat your child will learn
- Explain friction and air resistance
- Describe ways to reduce friction
- Distinguish mass and weight
- Calculate weight
The method
- W = m x g.
- Units.
- Multiply.
- Newtons.
Key words: friction, air resistance, mass, weight, gravitational field strength, newton.
Worked examples
The first three practice questions from the lesson, with every step.
Question 1
What is friction?
- Step 1: Rub
Answer: a force between surfaces that opposes motion
Question 2
Which direction does friction act?
- Step 1: Against
Answer: against the motion
Question 3
Give one useful effect of friction.
- Step 1: Grip
Answer: grip / brakes