Stopping distances, reaction times, momentum and changes in momentum

What is stopping distance?

Stopping distance is the total distance a vehicle travels from the moment the driver realizes they need to stop until the vehicle comes to a complete stop.

What factors affect stopping distance?

Factors include the vehicle’s speed, the driver’s reaction time, road conditions, and the condition of the brakes.

What is reaction time?

Reaction time is the time it takes for a driver to respond to a stimulus, such as seeing an obstacle ahead.

How is momentum calculated?

Momentum is calculated using the formula: Momentum = Mass × Velocity (p = m × v).

What is the unit of momentum?

The unit of momentum is kilogram meters per second (kg·m/s).

How does momentum change during a collision?

During a collision, momentum is transferred between objects, and the total momentum before and after the collision is conserved (law of conservation of momentum).

How does the mass of an object affect its momentum?

An object with a greater mass or velocity will have greater momentum.

What is the principle of conservation of momentum?

The principle of conservation of momentum states that the total momentum before a collision is equal to the total momentum after the collision, provided no external forces act.

How does an airbag help reduce the impact during a crash?

Airbags increase the time over which the collision happens, reducing the force on the body and thus reducing injury.

How does the velocity of an object affect its momentum?

Momentum increases with velocity, meaning faster objects have greater momentum.

What happens to momentum in a perfectly inelastic collision?

In a perfectly inelastic collision, the objects stick together, and momentum is conserved, but kinetic energy is not.

What is the relationship between impulse and momentum?

Impulse is the change in momentum, and it is calculated as Force × Time.

How can you reduce the momentum of a moving vehicle safely?

Braking, friction, and airbags are ways to reduce momentum safely, as they reduce speed over time.

How does the mass of a vehicle affect its stopping distance?

A heavier vehicle requires a longer distance to stop because it has more momentum and requires more force to decelerate.

What is the relationship between momentum and force?

The change in momentum is equal to the force applied multiplied by the time the force is applied (Impulse = Force × Time).