## Mechanics 1 Summary

This is a very succinct summary of the M1 module under the OCR MEI specification. M1 is just concepts and practice, really.

__Vectors__

Unit vector – has length 1; e.g. unit vector in direction 3i-5j is

Two vectors are parallel if they are multiples of each other.

Distance-time, displacement-time graphs – speed/velocity is the gradient.

Velocity-time – acceleration is the gradient, displacement is the area under the graph.

__Motion__Distance-time, displacement-time graphs – speed/velocity is the gradient.

Velocity-time – acceleration is the gradient, displacement is the area under the graph.

__Constant acceleration formulae____Variable acceleration__

**LEARN**

Horizontally – ONLY use s=ut.

Vertically a=-g (take upwards as positive unless the particle is projected downwards initially.)

For maximum height – use v²=u²+2as

For time of flight – use s=ut+ ½at². Remember that s is displacement.

For range use s= horizontal velocity x time of flight

Wires, strings – tension only

Rods – tension or thrust

Surfaces – reaction force outwards

Resolve forces into two directions – in the direction of potential motion and perpendicular to that direction. Use F=ma.

For equilibrium the resultant force in any direction is zero.

For connected particles, consider the forces on each particle separately.

__Projectiles__Horizontally – ONLY use s=ut.

Vertically a=-g (take upwards as positive unless the particle is projected downwards initially.)

For maximum height – use v²=u²+2as

For time of flight – use s=ut+ ½at². Remember that s is displacement.

For range use s= horizontal velocity x time of flight

__Forces__Wires, strings – tension only

Rods – tension or thrust

Surfaces – reaction force outwards

Resolve forces into two directions – in the direction of potential motion and perpendicular to that direction. Use F=ma.

For equilibrium the resultant force in any direction is zero.

For connected particles, consider the forces on each particle separately.