SPH4UE - Unit 1: Dynamics

Kinematics

The motion of objects without reference to forces

Dynamics

The study of forces and their influence on the motion of objects

Scalar

A quantity that is fully described by its magnitude

Vector

A quantity that is fully described by both its magnitude and direction

Methods to solve projectile motion problems

Pythagorean, SOHCAHTOA, v = d/t if constant acceleration, kinematics equations

y vector component formula

y = v*sinθ

x vector component formula

x = v*cosθ

Projectile motion in the horizontal direction is…?

Constant

Projectile motion in the vertical direction is…?

Accelerating/changing

What does time of flight depend on?

Only vertical variables

Projectile motion

The movement of an object projected into the air that is only affected by gravity

Frame of reference

A coordinate system in which motion is being described

Inertial frame of reference

A frame of reference moving at zero or constant velocity

Non-inertial frame of reference

A frame of reference that is accelerating

Relative motion

Motion relative to a frame of reference

Methods to solve relative motion problems

Trigonometry (SOHCAHTOA, Pythagorean)

First law of motion (law of inertia)

An object at rest stays at rest; An object in motion stays in motion, at a constant speed in a straight line, unless acted upon by an unbalanced force

Second law of motion (law of acceleration)

The acceleration of an object is directly proportional to the mass of an object

Third law of motion (law of forces)

For every force exerted on an object, the object exerts a force on the first that is equal in magnitude and opposite in direction

Methods to solve forces problems

Fnet = ma, draw FBDS, remember connected masses part of the same system, Fgx and Fgy equations

Radial direction

The direction which points inwards/outwards to/from the centre of curvature of the object's path

Tangential direction

The direction that is perpendicular to the radius at a point tangent to the circular path of the object

Radial acceleration

The acceleration that an object moving in a circle experiences, pointing towards the centre of the circle

Centrifugal force

A fictitious force existing in a non-inertial frame of reference that appears to act on a body moving in a circular path in the direction away from the centre of the circle

Spring force

The restoring force resulting from the elongation or compression of a spring

Hooke's law

The amount of distortion is proportional to the amount of distorting force

Momentum

Vector quantity: mass * velocity

Inertia

The tendency of an object to resist a change in its motion

Varying force

A force whose magnitude/direction change over time/position

Methods to solve spring force/elastic potential energy problems

Energy bar charts (energy conservation), equations, grass method, set a zero-reference height

Elastic collision

A collision where both momentum and kinetic energy are conserved

Inelastic collision

A collision where momentum, but not kinetic energy is conserved

Heat, sound, deformation

Some kinetic energy in an inelastic collision is converted to?

Impulse

The rate of change of momentum of an object (Force applied * duration that it is applied)