A force is a push or pull that one object exerts on another
3 things a force can do to an object:
change its speed
change is shape
change its direction
various types of force:
Friction is a force that always opposes motion between 2 surfaces in contact.
Force= mass x acceleration
Weight= mass x g
G=gravitational acceleration on earth, we consider G as 10N/kg.
There are two forces that act upon a falling object=
When an object first starts falling the weight is greater than the air resistant but as it gains speed the air resistance increases causing the air resistant and weight to level.
Terminal velocity= when the object's weight equals the air resistance
vehicle stopping distance= thinking distance + braking distance
thinking distance: how far the car travels at constant speed before the driver reacts by applying the car brakes
braking distance: distance travelled by the car as it decelerates to a stop
Factors affecting stopping distance
as the speed increases, stopping distance increase
as the mass increases, force needed to stop car increases
dry weather=more friction, rainy=less friction, as water acts as lubrican
as reaction time increases, stopping distance increases (If driver was drunk, their reaction would be slower, so reaction time increases, hence stopping distance increases)
moment= force x perpendicular distance from the pivot
Hooke's Law= The extension is directly proportional to the stretching force.
Extension varies with applied force for helical springs, metal wires and rubber bands extensions vary with applied force because of their elastic limit.
3 things a force can do to an object:
change its speed
change is shape
change its direction
various types of force:
- push/pull
- tension-the pull at both ends of a stretch spring, string or rope
- compression
- thrust/upthrust
- load
- effort
- weight/gravitational
- electrical/electrostatic
- magnetic
Friction is a force that always opposes motion between 2 surfaces in contact.
Force= mass x acceleration
Weight= mass x g
G=gravitational acceleration on earth, we consider G as 10N/kg.
There are two forces that act upon a falling object=
- Earth's gravity-Weight pulls object (downwards towards the centre of the Earth)
- air resistance/drag (upwards force, pushes object upwards)
When an object first starts falling the weight is greater than the air resistant but as it gains speed the air resistance increases causing the air resistant and weight to level.
Terminal velocity= when the object's weight equals the air resistance
vehicle stopping distance= thinking distance + braking distance
thinking distance: how far the car travels at constant speed before the driver reacts by applying the car brakes
braking distance: distance travelled by the car as it decelerates to a stop
Factors affecting stopping distance
as the speed increases, stopping distance increase
as the mass increases, force needed to stop car increases
dry weather=more friction, rainy=less friction, as water acts as lubrican
as reaction time increases, stopping distance increases (If driver was drunk, their reaction would be slower, so reaction time increases, hence stopping distance increases)
moment= force x perpendicular distance from the pivot
Hooke's Law= The extension is directly proportional to the stretching force.
Extension varies with applied force for helical springs, metal wires and rubber bands extensions vary with applied force because of their elastic limit.