In figuring out force, according to Wikpedia, it's F = dp over dt. But what's the "d" for?

Question

I know that p is momentum and t is time, but it doesn't say what d is. Thanks.

Answer 1

The "d" is not a variable. It is a mathematical notation that represents taking the derivitave of a function. Taking derivatives (also called differentiation) is one of the central operations of calculus.

dp/dt should be read as "the derivative of p with respect to t"

You can look at it this way... dp/dt is the rate at which p changes over time. For example, suppose that an object with a mass of 2 kg is moving at 2 m/s (meters per second). That means that its momentum is 4 kg*m/s. Now suppose that it's velocity is increasing. That means that it's momentum is increasing too. You can measure the rate at which it's momentum increases. That rate is measured in "kg*m/s per second", which is written as "kg*m/s^2". It can be pronounced "kilogram meters per second squared".