Lots of fields can benefit from the concepts in calculus. In cases where relationships can be graphed, calculus can be used. Velocity, which is similar to speed but includes direction, is a result of the relationship between distance and time. How fast is a diver or a long jumper going upon impact (or at any point during the dive or jump). What path does a gymnast follow when she releases the uneven bars? How long does it take for a car to drive from Point A to Point B?
All of these questions can be answered using calculus.
In a graph of distance and time, velocity is the derivative. Chemicals react with one another, and calculations about the rates at which they react involve calculus. Engineers might use calculus for optimization. For instance, they can find the largest volume that can be held by a soda and/or pop can, while using the smallest possible amount of aluminum. They can also figure out the best size can top and bottom for optimal stacking ability.
Video game engineers might use various forms of calculus to simulate real-life situations. Depending on the angle that a force is applied, where should those angry birds land after sling-shot release? Will the pigs pay? Video games are steeped in calculus simulations.