Impulse

• Change in momentum

  1. Newton's original formulation of his second law was not expressed in terms of acceleration

  2. 'Motion' of a body changes when a resultant force acts on it

  3. Momentum of the body changes when a resultant force acts on it

  4. Impulse is the change in momentum of the body

  5. The average force acting on the body for a time causes a change in the momentum
• Impulse in a car crash

  1. How quickly the car stops determines the damage

  2. Force required to bring the car to a stop is determined by Newton's second law of motion

  3. Force determines the damage

  4. Describing the impulse in a collision considers both the force and the time over which the force acts
• Rapid deceleration requires a large force and often results in damage and injury
• Momentum = mass x velocity
• The impulse is equal to the change in momentum, which can be calculated by subtracting the initial momentum from the final momentum.
• The SI unit of momentum is kg m s-1
• Newton's third law states that if two objects interact, they exert equal and opposite forces on each other.
• In a head-on collision between two cars with equal masses but different velocities, the one with the higher speed will have more momentum and therefore experience greater damage upon impact.
• The SI unit of impulse is N s
• Force = rate of change of momentum/time
• A larger object will have more momentum than a smaller one with the same speed due to its greater mass.
• An object moving at high speeds has higher momentum compared to an object moving slowly because momentum depends on both mass and velocity.
• A moving object always has some momentum, while a stationary object does not.
• When an object collides with another object, its momentum changes due to the transfer or loss of energy during the interaction.
• Impulse = force x time
• Average acceleration = change in velocity / time taken
• Acceleration due to gravity (g) = 9.8 ms^-2
• To reduce the risk of injury during a crash, vehicles are designed with crumple zones - areas that deform under pressure to absorb energy from the impact and protect the occupants.