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Science Forces Test
24/05/18
Question | Answer |
---|---|
What are the different types of forces? | Push, pull and twist |
What Can Forces Do? | Accelerate, Decelerate, Change Shape, Change Direction and Stop |
How Do We Measure Forces? | We measure forces in newtons (N). To measure forces we use springs. On a spring balance the spring expands as the force is heavier and on a kitchen and bathroom scale the spring compresses. |
What Is Inertia? | The tendency to resist a change in motion |
What Is Friction? | The force that acts against an object's motion. Unlike gravity friction is a contact force. |
What factors affect the amount of friction? | How rough the surface is, more bumps mean more friction, and the pressure, how hard the surfaces are rubbed together. |
What Is Useful Friction? | Traction (grip). Without traction we wouldn't be able to pick things up, hold things, walk etc. |
What Is Unwanted Friction? | Heat. When the parts in a car's engine rub together they create heat. This could cause the car's engine to over heat. |
How Can We Reduce Friction? | We can use lubricants, avoiding contact, shape, wheels. |
What Is Gravity? | A non-contact force of attraction between two objects. |
Contrast Balanced and Unblanced | Balanced is when all the forces acting on an object are equal. When this happens the object is either moving at a constant speed or has stopped. Unbalanced is when the forces acting on an object aren't equal. |
Contrast Weight and Mass | Weight change talks about the gravitational pull on an object. So if you go to a different planet your weight will be different because it's gravitational pull will be different. Mass is the compacted matter in an object so it won't change. |
Falling leaf & rock. | The heavier the object the faster it falls. So the rock will fall first. But if the leaf and the rock weigh the same the one with the most surface area will fall last because it has more air resistance. |
What Is Terminal Velocity? | The point at which an object falls at a constant speed. |
What Is The Strongest Part Of A Magnet? | It's poles. There are north and south poles. |
What Is The Difference Between A Permanent And Temporary Magnet? | Permanent magnets stay magnetised for a very long time. If a magnet is temporary it means that the magnets move. |
What Are Atoms? | Atoms are made of protons, neutrons and electron |
What Is Static Electricity? | Built up charge. When 2 surfaces are rubbed against each other the electrons will move and the object will become positively charged. |
What Does A Machine Do? | It makes our tasks easier |
Machines Work In 3 Different Ways. What Are They? | - Change size of force (eg toaster) - Makes things speed up (eg vacuum) - Changes direction of force (eg steering wheel) |
What Is A Force Multiplier? | A machine that increases the force that is applied onto a task |
How Is A Wheel A Force Multiplier? | It increases the force that you apply onto it's centre which allows it's axle to turn. It reduces friction. |
How Are Gears A Force Multiplier? | When you turn one gear all the other gears turn as well |
How Is An Inclined Plane A Force Multiplier? | An inclined plane allows you to travel a longer distance with less effort. |
How Is A Screw A Force Multiplier? | A screw allows you to use less effort over a longer distance because of it's ridges. |
What Is A Lever? | A lever is a simple machine that is made from a long, ridged object such as a metal rod or a stick |
What Are Three Types Of Levers? | 1st Class 2nd Class & 3rd Class |
What Is 1st Class? | When the fulcrum is in the middle |
What Is 2nd Class? | When the load is in the middle |
What Is 3rd Class? | When the effort is in the middle |
What Is A Speed Multiplier? | A speed multiplier increase the speed of a force. Eg. Microwave, vacuum, blender etc. |
How Does A Pulley Work? | A pulley is a wheel with a groove in it, onto which a rope or chain moves (eg blinds) |