- #1
NekotoKoara
- 18
- 2
Hello,
Over the past couple of weeks I have been working my way through the basics of physics on my own. I've just arrived at work and energy and there is one thing that confuses me a little bit. Let's say I have a 25kg box on a sidewalk. I go to push it and I ultimately push it 5m east (lets say east is the positive direction in this example) over a period of 5 seconds. Normally I see physics problems already include a specific force acted on the box by the person pushing it. For example they will say Sally pushed a box 5 meters with a force of 20 Newtons. Therefore Sally exerted 100 joules of work. But what if the force exerted is unknown? How would you derive the force from the information I provided (25kg box, +5m, 5 seconds)? Is it even possible to derive from that information? If not, what other information would be required to figure out the force that was applied?
The biggest point of confusion for me is the acceleration. If this were discussing an object dropping down with gravity acting on it then it seems much more straight forward since gravity, for the most part, is pretty consistent at Earth's surface. However a horizontal push, in real life, could be much more inconsistent. The box could start at 0m/s then accelerate up to 1m/s over a period of 1 second, have a constant velocity for 2 seconds, then over the rest of the journey accelerate back down to 0m/s. Or it could have any other of an infinite amount of velocities over an infinite amount of periods of time during that 5 second period. Is there some fundamental concept that I am completely missing or misunderstanding that will help alleviate my confusion?
Sorry if this is at all unclear. Any sort of help clearing this all up for me would be greatly appreciated. :-)
Over the past couple of weeks I have been working my way through the basics of physics on my own. I've just arrived at work and energy and there is one thing that confuses me a little bit. Let's say I have a 25kg box on a sidewalk. I go to push it and I ultimately push it 5m east (lets say east is the positive direction in this example) over a period of 5 seconds. Normally I see physics problems already include a specific force acted on the box by the person pushing it. For example they will say Sally pushed a box 5 meters with a force of 20 Newtons. Therefore Sally exerted 100 joules of work. But what if the force exerted is unknown? How would you derive the force from the information I provided (25kg box, +5m, 5 seconds)? Is it even possible to derive from that information? If not, what other information would be required to figure out the force that was applied?
The biggest point of confusion for me is the acceleration. If this were discussing an object dropping down with gravity acting on it then it seems much more straight forward since gravity, for the most part, is pretty consistent at Earth's surface. However a horizontal push, in real life, could be much more inconsistent. The box could start at 0m/s then accelerate up to 1m/s over a period of 1 second, have a constant velocity for 2 seconds, then over the rest of the journey accelerate back down to 0m/s. Or it could have any other of an infinite amount of velocities over an infinite amount of periods of time during that 5 second period. Is there some fundamental concept that I am completely missing or misunderstanding that will help alleviate my confusion?
Sorry if this is at all unclear. Any sort of help clearing this all up for me would be greatly appreciated. :-)