What is the required stopping force when a tractor-trailer combination accelerates to 100 km/h and needs to stop in seven seconds?

Answer: D — 9 times more than the acceleration force

To determine the required stopping force for a tractor-trailer combination accelerating to a speed of 100 km/h and needing to stop in seven seconds, we can use the concepts of dynamics, particularly Newton's second law of motion, which states that force is equal to mass times acceleration (F=ma). First, we calculate the necessary deceleration to stop from 100 km/h (which is approximately 27.78 m/s) in seven seconds. The deceleration can be found using the formula: Deceleration (a) = (final velocity - initial velocity) / time Here, the final velocity is 0 m/s since the vehicle comes to a stop, and the initial velocity is the computed speed in m/s. This gives: a = (0 - 27.78 m/s) / 7 s ≈ -3.97 m/s² This means a force must be applied in the opposite direction to achieve this deceleration. According to Newton's second law, the stopping force required can be expressed as the mass of the vehicle multiplied by this calculated deceleration. When considering stopping force relative to acceleration force, the total stopping force must not only counteract the current speed of the vehicle but also account for the additional factors