physics momentum

• momentum = mass x velocity
• 5 types of collision are: static, rear-end,  head on,the sticky and explosion
• inelastic collision is when there's no change in kinetic energy during the collision.
• In an elastic collision, there are two objects with equal masses moving at different speeds that collide head-on and bounce off each other without losing energy.
• collisions are events where two objects collide with one another, transferring energy between them.
• in the head on collision both objects stop completely
• total momentum before  = total momentum after

        
• if we have a closed system, meaning nothing can enter or leave, then the total momentum remains constant.
• Sticky collision

  
• Head on collision

  
• Explosion collision

  
• Stopping = thinking distance + breaking distance
• The stopping distance depends on the speed at which the vehicle was travelling
• Breaking distance is how long it takes for the car to stop once the brakes are applied
• Thinking distance is when your brain tells your foot to press down on the brake pedal
• Breaking distance is how long it takes for the car to stop once the brakes are applied
• passive safety features: airbags, seatbelts, crumple zones these are designed to make the experience comfortable and reduce chance of accident
• active safety features: airbags, seatbelts, crumple zones, automatic braking designed to protect services occupant in event if collision. Thus is fine by slowly absorbing vehicle's kinetic energy by extending collision time and reduce force acting in the occupants.
• The centre of mass of an object is the point on the object where the mass can be thought to be concentrated. 
• momentum is the product of mass and velocity, and is a vector quantity.