Kaplan Nursing Entrance Practice Exam

How does increasing the speed of an object generally affect the force required to stop it?

1. It decreases the required force

2. It increases the required force

3. It has no effect on required force

4. It doubles the required force

The correct answer is: It increases the required force

Increasing the speed of an object affects the force required to stop it due to the relationship between momentum and force. As the speed of an object increases, its momentum also increases, since momentum is the product of mass and velocity. When you need to bring that object to a stop, the force applied must counteract the momentum to reduce it to zero. According to the impulse-momentum theorem, the change in momentum is equal to the impulse applied to the object (which is the force times the time over which it acts). Therefore, if the object is moving faster, a greater change in momentum is required to stop it, meaning the force that must be applied must be larger to achieve that change in momentum over the same amount of time or over an extended period. This means that a higher speed directly correlates with a greater force requirement to stop the object in a given time frame, supporting the conclusion that the force needed increases as the object's speed increases.