IB HL Physics (2023) - Space Time and Motion

A.1-A.4

vector ☆

a quantity that has magnitude and spatial direction

scalar

a quantity with only magnitude

displacement-time graphs

gradient = velocity

velocity time graphs

gradient = acceleration

area = displacement

acceleration time graph

area = change in velocity

key features of projectile motion

• gravity the only force

• U_h = V_h

impact of drag on projectile motion ☆

• reaches a lower height

• travels less far horizontally

• the path becomes asymmetrical with the section before the peak longer

terminal velocity (parachute) ☆

• weight pulls person down

• drag begins to act

• terminal velocity is reached

• parachute opens and drag increases

• *slower* terminal velocity reached

Contact forces

• buoyancy

• friction

• drag

• normal reaction force

• tension

Non-Contact forces

• magnetic force

• electrostatic force

• weight

coefficient of friction

every pair of materials has a coefficient and it’s dependent on composition

translational equilibrium

when the sum of all forces = 0
Translational equlibrium will take place and V will be constant

unbalanced forces ☆

the sum of all forces acting on an object is Mass * acceleration and the object is accelerating

conservation of momentum

total momentum before = total momentum after

elastic and inelastic collisions ☆

elastic - total ke before = total ke after

inelastic - total ke before ≠ total ke after

when objects stick together after a collision it is always inelastic

impulse

the product of the average force * the time the force is acting

vector force

angular motion

motion along a circular trajectory

Centripetal Force ☆

The label given to the resultant force which acts from the circumference towards the centre of the circle

Principle of Conservation of Energy

Energy can not be created or destroyed, only transferred between stores

Ways of Transferring energy

• Mechanically

• Electrically

• By Heating

• By Radiation

Work

The amount of energy transferred from one energy store to another

GPE

the amount of energy an object has due to it’s position in a gravitational field

Power

Rate at which energy is transferred

Efficiency

the ratio of how much energy was put in to how much useful energy was put out.

Specific Energy

Number of Joules that can be released by each Kilogram of the source

Energy Density

Number of Joules that can be released by each metre cubed of the source

Angular displacement

the number of radians an object has rotated through (rad)

Angular velocity

the rate of change of angular displacement (rad s^-1)

angular acceleration

rate of change of angular velocity (rad s^-2)

Moment of Inertia ☆

the quantity that determines the torque needed for a rigid body to have a certain angular acceleration about a rotational axis (Kgm²)

Angular Momentum

The rotational equivalent of Linear Momentum (Kgm²s^-1)

Conservation of Angular Momentum ☆

The total angular momentum of a closed system remains constant providing no external torque acts on the system.

Torque

The twisting/Turning effect of a force on an object around a pivot or axis (Nm)

Couple ☆

a pair of equal and opposite forces that do not act in the same straight line but produce a resultant torque

Rotational Equilibrium

When Sum of the Clockwise Torques = Sum of the Anticlockwise Torques the rigid body is in rotational equilibrium

a.5 starts here lol

a.5 starts here lol