Work is the connection between force and displacement. In the Physics language, the answer to the same question, ‘what is work,’ has a different meaning. are some common examples where the subjects are performing work. A student is learning his course for the upcoming exams a musician is playing the flute a businessman is thinking of a meticulous plan for his business deal a child is riding a bicycle on the circular path in the park every day, etc. Work is a person’s function, duty, assignment, or special task. The question ‘what is work’ in general language can be defined as an activity in which one exerts physical or mental strength or performs something. The word work contains a dictionary meaning ‘to do something which needs physical or mental efforts, to earn money or to achieve something.’ The job you do, especially to earn money, is called work. This article aims to develop the understanding of a physical quantity called work in Physics. And what is work in Physics? This article will explain it to you. A teacher teaching in the class, a student doing his homework, a farmer ploughing his fields, a driver driving a car, an artist drawing a beautiful painting, a photographer clicking photos, etc., all are said to be working.īut, have you ever thought that Science has another perspective for the term ‘Work?’ Yes! This word, work in Physics, conversely has a definite and precise meaning. If you change the starting speed of the car, which vehicle stops in the shortest time? It's your turn to do the physics.The word work is generally one that every one of you frequently uses in your daily life. What kind of starting velocity would the car require to stop in the same distance as the truck? No, I am not revealing the answer. That's the explanation.īut wait! I have one more question for you as homework. With a greater work, the force has to be applied over a larger distance. The car starts with a higher kinetic energy and thus requires more work to stop it. But since kinetic energy depends upon the square of the velocity, the higher car velocity matters much more than the lower mass. The car has a lower mass, so it must have a higher velocity in order to have the same momentum as the truck. The fact the two vehicles have the same starting momentum doesn't mean they have the same starting kinetic energy. With the same force, this would be the same stopping distance. If the vehicles started with the same kinetic energy, it would take the same amount of work to stop them. Since the two vehicles will have the same acting force on them, I can compare stopping distances by looking at the change in kinetic energy. To find the distance it takes an object to stop, I must use the work energy principle. When determining the time required to stop an object, it makes sense to use the momentum principle since it deals with time. An arrow represents the velocity of the car.Ĭlearly, the red truck stops first. I did that so you see how fast they are moving. You'll notice the two vehicles leave a trail of dots. The big red box represents the truck and the small blue box is the car. Just press play to run it and the pencil to see (and edit) the code. This content can also be viewed on the site it originates from. The initial momentum is 20 kg*m/s and the stopping force is 2 newtons.Ī plot of the x-velocity for the car and the truck looks like this: We'll say the car has a mass of 10 kg (it's a really small car) and the truck has a mass of 30 kg (three times the mass of the tiny car). Of course, that requires some actual values for the mass of the two vehicles, the starting momentums, and the stopping force. Just for fun, let's create a numerical calculation for this. The cars stop at the same time because they start with the same momentum. According to the momentum principle, they must have the same change in time.Ĭlearly, answer number 2 is correct. In the end, both vehicles will have the same force with the same change in momentum. However, it starts with a much larger velocity since the two vehicles have the same starting momentum. Yes, it's true that the car has a lower mass and a higher acceleration. This, in turn, causes the car to slow down more quickly because the truck has a large mass and a small acceleration.Īnswer number 2: They stop in the same amount of time. ![]() Since it has lower mass, the force acting on it results in larger acceleration. However, since I'm not there and you aren't here, I will just share two common answers people provide.Īnswer number 1: The light car stops first. If you like, you can check with friends to see what they think.
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