We know work and power to be things that we hear in our daily lives, whether it’s working at a hospital to having the power to rule the world. But, in the world of physics, the terms work and power are use when someone wants to calculate the amount of energy in a certain situation. Work is the effort exerted on something that will change its energy. The heavier something is or the higher something is, more work is done. To calculate work, you need to find how much force is applied to an object and the distance in which the object is moved. The formula easily converts to: work = force times distance / W (joules)= F (Newtons) x d (meters). So if, let’s say, you want to calculate how much work is needed to lift a pack of soda that weighs 300 N to a flight of stairs that’s 2 meters high. To find the solution, simply insert the components for the formula and the final answer is: 600 J.
When you want to find how much power is used in a certain situation, you need to find the amount of work done and the time it takes. Hence the formula for power: power (Watts) = work (joules) / time interval. To put it more generally, power is the rate at which energy expands. When it comes to doing the same amount of work or a certain action, more power will be calculated if someone does twice the amount of work in the same time or the same amount of work in half the time. Let’s use the same example above and say, how much power is used when you lift a pack of soda weighing 300 N up 2 meters in 20 seconds. Since you already found how much work, which is 600 J. So, all you have to do is divide 600 by 20, which results to 30 watts.
Let’s do another example:
How much power expends when a 20-N force pushes a cart 3.5 meters in a time of 0.5 seconds?
First, you have to find the work done. Going back to the formula of work, w = f x d, you have the force and distance given. So, you multiply 20 by 3.5, resulting to 70 joules. With the work found, you can found the power: you divide 70 by 0.5, resulting in 140 watts.
To conclude, without knowing the work done in an action, you won’t know the power.