# Section 1 Forces and Motion

Velocity and Acceleration

Speed: How fast you are going. =distance/time m/s

Acceleration: How fast your velocity is changing. =change in velocity/time taken m/s squared

D-T and V-T Graphs

D-T:

• Steeper= Faster.
• Downhill= going back towards the starting point.
• Curves= Accelerating and Decceleration.
• Steepening= speeding up.
• Levelling off= Slowing down.

Speed= Vertical/Horizontal

V-T:

• Steeper= Greater the acceleration or decceleration.
• Area under= Distance travelled.
• Curve= Changing acceleration.

Mass, Weight and Gravity

Gravity is force of attraction between all masses. It makes things accelerate towards the ground at 10m/s squared.

• Mass is the amount of stuff within an object.
• Weight is just the force of gravity pulling somthing towards center.

Weight(n) = mass(kg) x gravitational field strength(10).

Friction and Forces

Forces: Gravity, Reaction (caused by surface), Electrostatic (two charged objects), Thrust (engine or rocket), Lift, Tension (rope or cable).

Anything with a force feels a reaction force

Friction is always there.

Terminal Velocity

When something starts falling it accelerates due to little resistance…