Final answer:
It's harder to stop a truck than a car at the same speed due to Newton's first law of motion, which requires a greater force to alter the larger mass and momentum of the truck.
Step-by-step explanation:
Understanding Why It's Harder to Stop a Truck than a Car
The reason it's harder to stop a truck than a car moving at the same speed is explained by Newton's first law of motion. This law states that an object in motion will stay in motion at a constant velocity unless acted upon by an external force. When you have a truck and a car moving at the same speed, the truck has a larger mass compared to the car, which means it has greater momentum. Consequently, a greater force is required to change the state of motion, which makes it harder to stop the truck.
Friction is an essential force in stopping both the car and the truck as it acts opposite to the direction of motion. This resistance to motion is what slows and eventually stops the vehicle. However, given the larger mass and momentum of the truck, overcoming this inertia requires a more substantial amount of friction, or otherwise, a longer distance or a stronger braking force to bring the truck to a stop compared to the car.
To succinctly summarize Newton's first law, an object will continue to be at rest or move at a constant speed in a straight line unless it is compelled to change its state by an external force, like friction. This fundamental concept of physics helps explain many everyday phenomena, including vehicle dynamics.