science test w6 t4

Force

Force

Interaction between two or more objects, with a push, pull, or both (a twist).

Balanced Forces

Equal forces acting in opposite directions.

Unbalanced Forces

Unequal forces causing a change in motion.

Inertia

Resistance of an object to change its motion.

Friction

a force which opposes relative motion between two surfaces in contact with each other.

Fluid Friction

Friction when moving through liquid or gas.

Sliding Friction

Friction when two surfaces slide over each other.

Rolling Friction

Friction when a circular object rolls.

Static Friction

Friction preventing motion of a stationary object.

Weight

Gravitational force acting on an object's mass.

Terminal Velocity

Constant speed when air resistance equals weight.

Magnetic Field

Space around a magnet where magnetic force exists.

Magnetic Poles

Regions of a magnet that attract or repel.

Temporary Magnet

Magnetized by external magnetic influence.

Permanent Magnet

Retains magnetic properties without external influence.

what are the parts of a lever

rigid bar, fulcrum, load, effort

Electrical Conductors

Materials allowing easy electron flow, e.g., metals.

Static Electricity

Charge imbalance due to electron transfer.

Non-contact Forces

Forces acting at a distance, e.g., gravity, magnetism.

Force Field

Region where a force acts without contact.

Non-contact force

A force acting at a distance without physical contact.

Gravity

Attractive force between masses, keeping planets in orbit.

Air resistance

Opposing force acting on objects moving through air.

Magnet

Material that attracts iron, cobalt, or nickel.

Magnetic field

Space around a magnet where magnetic forces act.

Magnetic poles

Ends of a magnet where the magnetic field is strongest.

Like poles

Same magnetic poles that repel each other.

Unlike poles

Different magnetic poles that attract each other.

Magnetic domains

Tiny magnetic particles in certain metals acting as magnets.

Simple machine

Device that makes life easier by changing the direction or size of a force.

Lever

Rigid bar rotating around a fulcrum to lift loads.

Fulcrum

Pivot point around which a lever rotates.

Inclined plane

Flat surface tilted at an angle to reduce effort.

Wedge

An inclined plane turned on its side, used to split objects.

Screw

A rigid bar that has an inclined plane spiralled around it with a pointed tip used to fasten things together.

Mechanical advantage

Ratio of output force to input force in machines.

First class lever

Fulcrum between effort and load, e.g., scissors.

Second class lever

Load between fulcrum and effort, e.g., wheelbarrow.

Third class lever

Effort between fulcrum and load, e.g., fishing rod.

Ramp

Inclined plane used to raise or lower objects.

Inclined plane examples

Slides, ramps, and driveways facilitating movement.

Wedge examples

Nails, knives, axes, and incisors.

Magnetic field lines

Indicate direction of magnetic force, do not cross. when they are spaced further apart they represent a weaker magnetic force. They always run from north to south pole

Earth's magnetic field

Generated by molten rock movement in Earth's core.

Wheel and axle

A type of simple machine. It consists of a round disk, known as a wheel, with a rod through the centre of it, known as the axle.

Pulley

A simple machine that changes the direction of a force, often to lift a load. It is a wheel and axle with a rope or cable wrapped around it.

Force multiplier

A mechanism that increases the force applied to perform a task.

Gear

A rotating circular machine part having cut teeth or inserted teeth that mesh with another toothed part to transmit torque and speed.

Gear train

A set of gears that are connected.

Driving gear

The gear that supplies the force in a gear system.

Driven gear

The gear that is connected to the driving gear.

Gearing down

A combination of gears where the driving gear is smaller than the driven gear, acting as a force multiplier.

Gearing up

A combination of gears where the driving gear is larger than the driven gear, acting as a speed multiplier.

Mechanical Advantage

The advantage a machine gives you to do work.

Torque

A measure of the force that can cause an object to rotate about an axis.

Linear force

A force that moves an object in a straight line.

Redirect force

To change the direction of your push or pull to gain advantage over a task.

Spoke

Each part of a wheel that acts as a lever.

Effort force

The force applied to a machine to perform work.

Distance

The length over which a force is applied.

acceleration

speeding up

deceleration

slowing down

how can you reduce friction

Make the surfaces little more smoother, Lubrication, make contact surface smaller

is friction good or bad

It can be both; friction is necessary for movement and traction, but excessive friction can cause wear and energy loss.

How do forces change motion

A net force on an object changes its motion – the greater the net force, the greater the acceleration. More massive objects require bigger net forces to accelerate the same amount as less massive objects.

How do magnets work

Magnets work because of tiny particles called electrons. These electrons spin and create small magnetic fields. In most things, these fields cancel out. However, in certain materials, like iron, the tiny magnetic fields align in the same direction.

how many simple machines are there

7

what are the simple machines

lever, wedge, gear, wheel and axle, pulley, incline plane and screw

how have inclined planes evolved over history

Inclined planes have been used by people since prehistoric times to move heavy objects. The sloping roads and causeways built by ancient civilizations such as the Romans are examples of early inclined planes that have survived, and show that they understood the value of this device for moving things uphill.