Momentum Conservation: According to the law of conservation of momentum, the total momentum of a closed system remains constant. Momentum is defined as the product of mass and velocity, and it is a vector quantity. When brakes are applied to a moving truck, the force exerted by the brakes generates a negative acceleration, causing the momentum of the truck to change. To reduce the momentum of the heavier loaded truck to the same extent as the lighter empty truck, the brakes must apply more force.
Kinetic Energy and Work: Kinetic energy is the energy possessed by an object due to its motion, and it is directly proportional to both mass and velocity squared. When a truck needs to stop, its kinetic energy must be dissipated as heat and sound energy through the braking process. The increased mass of a loaded truck results in higher kinetic energy, requiring more work (force acting through a distance) to dissipate this energy and bring the truck to a stop.
Tire Grip and Friction: The friction between the tires and the road surface is a crucial factor in stopping a truck. The additional weight of the load in a loaded truck increases the normal force exerted on the tires, enhancing the frictional force. However, the increased frictional force alone may not be sufficient to counter the truck's higher momentum, making it more challenging to stop quickly. Therefore, the brakes need to apply greater pressure to overcome this challenge.
