q('~What is the word in physics for the pushing and pulling that cause the acceleration of an object? ~force~It can be sometimes be measured by the amount it stretches a spring.~Gravity, magnetism and wind or moving water are all examples of a force.~');
q('~What is the unit of measurement of force? ~newton~The word comes from the name of a famous British scientist.~A force of 1 newton gives an acceleration of 1 m/s<sup>2</sup> to a mass of 1kg.~');
q('~What is the word for the increase in velocity (speed) of an object? ~acceleration~Think of the name of the pedal in the car that you press to make the car go faster.~The opposite of acceleration is deceleration.~');
q('~What is the word for the amount of matter in something? ~mass~This does not change for an object on earth and the same object on the moon.~Mass is measured in kilograms.~');
q('~Which British scientist investigated forces in the 18th century? (last name only) ~Newton~His first name was Isaak.~He gave his name to the unit measuring the pull of gravity.~');
q('~What do we call the slowing-down force of two objects rubbing together? ~friction~We use oil to reduce this in the moving parts of a car or bike.~Friction is the force used to stop or slow down a bike~');
q('~What is the name of the force that exists between two objects? ~gravity~This is the force pulling objects to the center of the earth.~Gravity  is responsible for keeping the moon in orbit around the earth.~');
q('~What is the name of the force that results from the downward pull of gravity? ~weight~This is what you measure when you step on the scales in the bathroom.~Weight can be measured in newtons.~');
q('~What is the name for the force that pushes up on a boat, allowing it to float? ~buoyancy~This force is not strong enough to stop some objects from sinking.~This upward force is strong enough to keep huge metal ships afloat.~');
q('~What do we call a pushing down force spread out over an area? ~pressure~The air around us exerts this kind of force.~Air pressure is measured by a barometer.~');
q('~What is the name for the electrical force between two objects? ~static~This is the force that allows a rubbed balloon to be stuck on a wall or sweater.~The static electric force that flashes down from the sky in a thunderstorm is called lightning.~');
q('~What kind of force moves an object around a pivot? ~turning~This force allows you to put a screw into a piece of wood. ~The turning force is also used to twist of the top of a bottle.~');
q('~What is the name of the force which operates when a rope is pulled tight? ~tension~This is also the word for the feeling people have when they are nervous, frightened or worried.~If the tension on a pulled rope becomes too great, the rope will break.~');
q('~What is the name for the central point on which something turns or balances? ~pivot~A compass needle balances on this, allowing it to turn. (It is also called the fulcrum.)~The pivot of a see-saw is located in the middle of the plank of wood.~');
q('~What is another word for the speed at which an object travels in a particular direction? ~velocity~Acceleration is measured by the increase in this, divided by the time taken to increase it.~The velocity of a car going around a bend is different from the velocity of a car travelling in a straight line.~');
q('~What word describes objects or structures that are stiff and cannot easily be bent or pushed out of shape? ~rigid~It is important that the frame of a bike has this quality.~A triangle is a more rigid shape than a rectangle.~');
q('~Four of the basic machines are the lever, the wheel axle, the inclined plane and the screw. What is the fifth one? ~wedge~The axe is an example of this 5th kind of machine.~They are called machines because they make work easier to do.~');
q('~Which of the basic machines would you use if you wanted to push a heavy box up into a truck? ~inclined plane~Another word for this answer is <em>slope</em>.~You would have to move the box further than if you lifted it, but you would need less effort.~');
q('~<em>Which word is missing at the end of the following sentence:</em><br><br> Ice or oil on a road increase the braking distance because they reduce the .... . ~friction~This is the slowing down force when two substances rub together.~Friction is greatest with new tyres and a dry road.~');
q('~What word is used to describe an object that cannot be pushed over easily? ~stable~An object has this quality if it has a low center of mass or a broad base.~To prevent someone pushing you over easily, you should stand with your legs apart. This gives you a broad base.~');
q('~What kind of machine can multiply both force and distance? ~lever~Scissors or nutcrackers are examples of this kind of machine.~Class one and two levers are force multipliers; class three levers are distance multipliers.~');
q('~What is the name of the machine that uses ropes to help us lift heavy objects? ~pulley~This machine contains one or more wheels.~A pulley is a force magnifier when more than one wheel is used.~');
q('~What is the name for the turning point of a lever? ~fulcrum~Another word is <em>pivot</em>.~If the fulcrum is between the load and the effort, it is called a class 1 lever.~');
q('~<em>Which word is missing in the following sentence:</em><br><br> Nutcrackers are a class 2 lever. The .... is between the fulcrum and the effort. ~load~This is the larger force that is acted on by a machine.~The load in this case is the nut!~');
q('~What word, meaning the same as balance, is used when the (turning) force on one side of a fulcrum is the same as the force on the other side? ~equilibrium~The word comes from the Latin words for equal - weight.~Two children of equal weight sitting at an equal distance from the fulcrum of a seesaw will be in equilibrium.~');