Force is a push or a pull acting on an object as a result of its interaction with another object, measured in Newtons (N) and direction.
[5.1]
What are the 2 types of force?
Force can either be:
- Contact, between physically touching objects
- Non-contact, between non-touching objects
[5.2]
What is the difference between vector and scalar quantities?
Vector quantities have both magnitude and direction, while scalar only have magnitude.
[5.3]
What do free body diagrams show?
Free body diagrams show all of the forces acting on an object and their directions.
[5.3]
Define resultant force.
The resultant force on an object is the overall force acting on it, which can be found by appreciating that opposite forces cancel out and other forces can combine directions.
[5.4]
What do scale drawings show?
Scale drawings can be used to find the resultant force from the forces acting on an object, or vice versa.
[5.5]
What are the 3 types of elasticity when force is applied to an object?
When force is applied to an object, it can:
- Compress
- Stretch
- Bend
[5.5]
What is the term for when an object is forced out of shape?
When an object is forced out of shape, it is referred to as deformed.
[5.5]
Give the 2 types of deformation.
The 2 types of deformation are:
- Elastic, object returns to original shape
- Inelastic/plastic, object does not return to original shape
[5.5]
Define extension in terms of springs.
Extension is the increase in length of a spring as a result of forces being applied to it.
[5.5]
What is Hooke's Law?
Hooke's Law states that force and a spring'sextension are directlyproportional (Force = Constant x Extension).
[5.5]
What is the limit of proportionality for a spring?
The limit of proportionality for a string is the maximum force that can be applied before it begins to deform inelastically, meaning force and extension are no longer directly proportional.
[5.6]
Give the formula for elastic potential energy.
Eₑ = ¹/₂ke²
Energy = ¹/₂ x Constant x Extension²
[5.7]
What is a moment?
A moment is the rotational effect of a force on an object around a central point.
[5.7]
Give the formula for moments.
M = Fd
Moment = Force x Distance
[5.7]
Why does the angle of force applied matter in moments?
A moment's power increases the closer it is to being perpendicular to the object, as more of the energy is exerted on rotating the object (head-on collision).
[5.8]
What is the purpose of levers?
Levers amplify an input force by producing an output force that is further from the pivot (and therefore larger).
[5.8]
What is the purpose of gears?
Gears transmit turning effects when interlocked.
[5.9]
What is pressure?
Pressure is a measure of force exerted per unit of an area.
[5.9]
Give the formula for pressure.
p = F / A
Pressure = Force / Area
[5.9]
How does the angle of a collision affect pressure?
The angle of a collision affects pressure as the closer the collision is to perpendicular, the more force is exerted on the surface (head-on collision).
[5.10]
Give the 3 factors for pressure on an object in a liquid.
The 3 factors for pressure on an object in a liquid are:
- Object depth
- Liquid density
- Gravitational field strength
[5.10]
Give the formula for pressure within a liquid.
P = hgp
Pressure = Height x Density x Gravitational Field Strength
[5.10]
What is upthrust?
Upthrust is a resultant force that acts on objects in a liquid, pushing them upwards.
[5.10]
How does an object's density affect buoyancy?
If an object's density is greater than the density of the liquid, the weight will counteract the upthrust and produce a resultant downward force, while a lesser density will produce a resultant upward force.
[5.11]
Where is atmospheric pressure the greatest and why?
Atmospheric pressure is greatest at sea level due to the greater number of particles above pushing downwards, creating more pressure.
[5.12]
What type of quantity are speed and distance examples of?
Speed and distance are examples of scalar quantities.
[5.12]
What type of quantity are velocity and displacement examples of?
Velocity and displacement are examples of vector quantities.
[5.12]
Give the formula for speed.
s = d / t
Speed = Distance / Time
[5.12]
What is the difference between speed and velocity?
Speed describes the magnitude of an object in motion, while velocity describes the magnitude as well as the direction of travel.
[5.12]
What is the difference between distance and displacement?
Distance describes the totallength of space travelled, while displacement describes the length between the start and end as a straight line.
[5.13]
What is acceleration?
Acceleration is the rate of change in the velocity of an object - which can be a change in speed or a change in direction.
[5.13]
Give the formula for acceleration involving time.
a = ∆v / t
Acceleration = ∆Velocity / Time
[5.13]
Give the formula for acceleration involving distance.
2as = v² - u²
2 x Acceleration x Distance = Final velocity² - Initial velocity²
[5.13]
What is the term used to describe acceleration at a consistent rate?
Acceleration at a consistent rate can be described as constant or uniform.
[5.14]
What does the gradient represent in a distance-time graph?
The gradient in a distance-time graph represents speed.
[5.14]
On a curving distance-time graph, how can speed be found?
On a curving distance-time graph, speed can be found through the usage of a tangent.
[5.15]
What does the gradient represent in a velocity-time graph?
The gradient in a velocity-time graph represents acceleration.
[5.15]
What does the area under the curve represent in a velocity-time graph?
The area under the curve in a velocity-time graph represents the total distance travelled.
[5.16]
What is terminal velocity?
Terminalvelocity is the point at which the air resistance and weight of an object cause a resultant neutral force, meaning there is no acceleration and velocity is constant.