| as an object moves further from the earths centre, what happens to gravitational field strength? | it decreases |
| define force | force is a push or pull that acts on an object due to its interaction with another object |
| what is force measured in | Newtons
N |
| when force is applied to an object, what can it change about an object? | shape
speed
direction of travel |
| what is meant by a balanced force | when there are no forces acting on an object
OR
the forces that are acting on an object cancel each other out |
| what is meant by an unbalanced force | when there is a net or resultant force acting on an object |
| what is newtons first law of motion? | an object at rest will remain at rest unless acted on by an unbalanced force
an object in motion continues in motion with the same speed and in the same direction unless acted on by an unbalanced force |
| what will happen if the forces acting on a stationary object are all balanced | the object will stay stationary |
| what will happen if the forces acting on a moving object are all balanced? | the object will continue moving at the same speed and in the same direction |
| what will happen if the forces acting on an object are unbalanced | the object will accelerate in the direction of the unbalanced force |
| calculate the resultant force acting on the football and describe its motion as a result | 3N resultant force to the left
Football will accelerate towards the left |
| what is terminal velocity? | the constant speed an object in free fall reaches when the air resistance prevents further acceleration due to gravity |
| what is friction | the force resisting the motion of surfaces sliding against each other |
| what are some advantages of friction | as we walk friction stops us from slipping
car tyres use friction to propel vehicle forward and allow them change direction |
| why are there grooves in tyres | provide space for water and oil to go and allow the tyre to be in contact with road surface |
| what is the affect of wider tires on frictional force | wider tyres provide a greater frictional force allowing cars to corner at a higher speed |
| how can friction be reduced? | lubrication (oil in an engine, jets of air in air hockey)
streamlining |
| what is streamlining? | when an objects shape creates as little resistance as possible from gases or liquids |
| What is newton's second law put simply? | The acceleration of an object is directly proportional unbalanced force and inversely proportional to an objects mass |
| what is the formula for newtons second law? | F=ma |
| In the formula F=ma, what is F? | Unbalanced force in Newtons |
| In the formula F=ma, what is m? | mass in kg |
| in the formula F=ma, what is a? | acceleration in ms⁻² |
| when an object moves at a constant speed, what is the net force on that object? | 0
all forces are balanced |
| what is mass | a measure of the number of particles in an object |
| what is mass measured in | kg |
| what is weight | the force of gravity acting on an objects mass
(on earth, the earths pull on us) |
| what is weight measured in? | Newtons |
| What does the weight of an object depend on | an objects mass
how far it is from the planets centre
gravitational field strength of the planet |
| what is gravitational field strength? | weight per unit mass or force of gravity per kilogram |
| what is gravitational field strength measured in? | N kg-1 |
| What is the formula for an objects weight? | W=mg |
| In W=mg, what is W? | Weight in Newtons |
| In W=mg, what is m? | mass in kg |
| In W=mg, what is g? | gravitational field strength in N kg-1 |
| as an object moves further from the earths centre, what happens to gravitational field strength? | it decreases |
| What is newtons third law? | for every action force there is an equal and opposite reaction force |
| Forces always exist in pairs. What are these pairs called? | Newton Pairs/ Paired Forces |
| describe what happens when you blow up a balloon in terms of newtons third law | The air particles exert a force on the balloon and the balloon exerts an equal and opposite force on the air particles. |
| How is a rocket launched according to Newton's third law? | Rocket engines force heated gas out of the end of the rocket, the heated gas exerts an equal and opposite force on the rocket, pushing it upwards. |
