Science: 2 Forces

Year 7 Science : Forces 1. What is a force?A force is a push or a pull.2. Types of forces:Examples are:Gravity – pulls things down.Friction – slows things down when they rub.Air resistance – slows things in the air.Upthrust – pushes up in water.3. Contact and non-contact forces:Contact forces touch the object (e.g. friction, push).Non-contact forces act without touching (e.g. gravity, magnetism).4. What can forces do to objects?Forces can:Change speed (faster/slower)Change directionChange shape5. How do we measure force?We use a newton meter and measure in newtons (N).6. What is mass and weight?Mass is how much stuff is in something (measured in kilograms, kg).Weight is the force of gravity pulling on mass (measured in newtons, N).7. How to show forces:Use arrows — the size shows how strong the force is, and the direction shows where it’s going.8. What does elastic mean?An elastic material stretches when you pull it and goes back when you let go (like a rubber band).9. Springs and force:A spring stretches more when a bigger force is used.10. How forces affect movement and shape:More force = more change. It can make things move, stop, or change shape.11. What is friction?Friction is a force that slows things down when two surfaces rub together.12. When is friction helpful or unhelpful?Helpful: car brakes, shoes stopping you from slipping.Unhelpful: trying to slide heavy furniture on carpet.13. How can we reduce friction?Use oil, smooth surfaces, or wheels to help things move easily.14. What are balanced forces?Balanced forces are equal — they don’t change movement (object stays still or keeps going at same speed).15. What are unbalanced forces?Unbalanced forces cause change — the object might start moving, speed up, slow down, or change direction.