Final answer:
The false statement about braking force is that it is inversely proportional to speed. Braking force is primarily a function of the vehicle's kinetic energy, which increases with the square of velocity.
Step-by-step explanation:
The statement about braking force that is false is: b) Braking force is inversely proportional to speed. This statement is incorrect because braking force is not dependent on the speed of a vehicle in a simple inverse proportional relationship. Rather, the braking force required to stop a vehicle is generally a function of the kinetic energy of the vehicle, which is directly proportional to the square of the velocity (KE = 1/2 mv²), and the efficiency of the braking system. More kinetic energy (a function of weight and velocity squared) will require more braking force to stop the vehicle.
As for the correct statements: a) is true because more weight means more force is required to counteract the momentum of the vehicle. c) is true as heavier vehicles have more kinetic energy and thus require a longer braking distance. d) is also generally true under the assumption that lighter vehicles, with less kinetic energy, require less force to stop, resulting in a shorter braking distance.