Higher Physics

Scalar

A quantity that can be described by magnitude alone

Vector

A quantity that can be described by magnitude and direction

Acceleration

Change in velocity per unit time

3 equations of motion

1. v=u+at
2. s=it+1/2at^2
3. v^2=u^2+2as

Projectiles at a vertical angle

Vv=vsin0

Projectiles at a Horizontal Angle

Vh=vcos0

SUVAT

S= Displacement (m)
U= Initial Speed (ms^-1)
V= Final Speed (ms^-1)
A= Acceleration (ms^-2)
T= Time (s)

Newton's 1st Law of Motion

An object will remain at rest or travel in a straight line at a constant velocity if the forces acting on it are balanced

Newton's 2nd Law of Motion

Fun= Ma
If an object experiences an unbalanced force, the object will accelerate in the opposite direction to which the forces applied

Newton's 3rd Law of Motion

For every action force there is an equal and opposite reaction force

Accelerating up in an elevator

Up: +
Accelerating: +
Reading(N) = W+F (Weight+Force)

Decelerating up in an elevator

Up: +
Decelerating: -
Reading(N) = W-F (Weight-Force)

Accelerating Down in an elevator

Down: -
Accelerating: +
Reading(N) = W-F (Weight-Force)

Decelerating Down in an elevator

Down: -
Decelerating: -
Reading(N)=W+F (Weight+Force)

tension

T=ma (Tension=mass x Acceleration)

Magnitude of force exerted on one block by another

F=ma rearranged to a=F/m then Force of Block A on Block B= ma

momentum equation

P=mv (momentum = mass x velocity)

Two masses collide and stick together

(m1u1)+(m2u2)=(m1+m2)v

Two masses collide & move apart with different velocities after the collision

(m1u1)+(m2u2)=(m1v1)+(m2v2)

An explosion: one mass explodes into two seperate masses which move off separately with different velocities

mu=(m1v1)+(m2v2)

elastic & Inelastic Collision calculation

Total Ek before Collision = (1/2m1u1^2)+(1/2m2u2^2)
Total Ek after collision= (1/2m1v1^2)+(1/2m2v2^2)

Impulse equation

F=ma
F= m(v-u)/t
F= m change in v/t
Ft= change in (mv)

Force time graphs

The area under a force-time graph is the impulse / change in direction, impulse is equal to the area under a force time graph

Airbags

An airbag slows the passenger speed to zero with little to no damage. To do this it needs to increase the time over which the change in speed (and momentum happens)

Crumple Zones

Crumple zones increase the time it takes for a vehicle to stop in the event of a crash, this reduces the force experienced by the driver and occupants on impact. Seatbelts also help with this

Galilean Invariance

The laws of physics are the same whether moving at a constant speed or at rest

Universal Law of Gravitation equation

Universal Law of Gravitation