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Physics Question

Originally posted by: randumb
Does a steep slope with less distance or a not so steep slope with longer distance require more work?
Click to expand...

Concerning gravity:

If you climp up a steep slope you will have to exert more energy compared to a more horizontal slope with a longer distance. Climbing the longer one will require less work for a longer period of time.
 
It's a problem for my physics class. It says you have a board against a wall. The board is leaned against the wall at different angles, and the ones with larger angles have less distance to the wall and the ones with smaller angles have less distance. It then asks if you dragged a block up each board and measured the force and did the work equation, which would require more work?
 
Originally posted by: randumb
It's a problem for my physics class. It says you have a board against a wall. The board is leaned against the wall at different angles, and the ones with larger angles have less distance to the wall and the ones with smaller angles have less distance. It then asks if you dragged a block up each board and measured the force and did the work equation, which would require more work?
Click to expand...

if there's no friction and the vertical displacement is the same, then the work spent are the same.
 
Originally posted by: randumb
It's a problem for my physics class. It says you have a board against a wall. The board is leaned against the wall at different angles, and the ones with larger angles have less distance to the wall and the ones with smaller angles have less distance. It then asks if you dragged a block up each board and measured the force and did the work equation, which would require more work?
Click to expand...
Assuming no friction, and the final height is the SAME in ALL cases, the work would be the same.
 
Originally posted by: godspeedx
Originally posted by: randumb
Does a steep slope with less distance or a not so steep slope with longer distance require more work?
Click to expand...

Concerning gravity:

If you climp up a steep slope you will have to exert more energy compared to a more horizontal slope with a longer distance. Climbing the longer one will require less work for a longer period of time.
Click to expand...


?????
 
Originally posted by: tyler811
Originally posted by: godspeedx
Originally posted by: randumb
Does a steep slope with less distance or a not so steep slope with longer distance require more work?
Click to expand...

Concerning gravity:

If you climp up a steep slope you will have to exert more energy compared to a more horizontal slope with a longer distance. Climbing the longer one will require less work for a longer period of time.
Click to expand...


?????
Click to expand...

🙁I see what you mean.
 
Originally posted by: godspeedx
Originally posted by: randumb
Does a steep slope with less distance or a not so steep slope with longer distance require more work?
Click to expand...

Concerning gravity:

If you climp up a steep slope you will have to exert more energy compared to a more horizontal slope with a longer distance. Climbing the longer one will require less work for a longer period of time.
Click to expand...

Less POWER for a longer period of time, but you'd still end up with the same amount of work. This is, as stated, of course neglecting friction. If you take friction into account, then the least work you could do would be to pick it straight up.
 
Guys, the heights are not the same. If you put boards against the wall, the ones with lower angles to the floor are going to have a lower point where they lean against the wall...
 
Originally posted by: Howard
Guys, the heights are not the same. If you put boards against the wall, the ones with lower angles to the floor are going to have a lower point where they lean against the wall...
Click to expand...

I think the length of the board makes it always long enough to reach a certain height at whatever angle.
 
Originally posted by: Legendary
Originally posted by: Howard
Guys, the heights are not the same. If you put boards against the wall, the ones with lower angles to the floor are going to have a lower point where they lean against the wall...
Click to expand...

I think the length of the board makes it always long enough to reach a certain height at whatever angle.
Click to expand...
In which case the work done will be different for all boards, correct? W = Fd (disregarding angle of net force), distance changes, whereas the force stays the same - at least, I'm assuming the force is applied at 0 degrees.
 
Originally posted by: Howard
Originally posted by: Legendary
Originally posted by: Howard
Guys, the heights are not the same. If you put boards against the wall, the ones with lower angles to the floor are going to have a lower point where they lean against the wall...
Click to expand...

I think the length of the board makes it always long enough to reach a certain height at whatever angle.
Click to expand...
In which case the work done will be different for all boards, correct? W = Fd (disregarding angle of net force), distance changes, whereas the force stays the same - at least, I'm assuming the force is applied at 0 degrees.
Click to expand...

Dude, you are thinking too hard. The amount of work will ALWAYS be the same if the height is always the same neglecting friction. If the angle is lower, the amount of work per unit time decreases, but the total time goes up inversly to the amount of work being performed per unit time.
 
Originally posted by: Evadman
Originally posted by: Howard
Originally posted by: Legendary
Originally posted by: Howard
Guys, the heights are not the same. If you put boards against the wall, the ones with lower angles to the floor are going to have a lower point where they lean against the wall...
Click to expand...

I think the length of the board makes it always long enough to reach a certain height at whatever angle.
Click to expand...
In which case the work done will be different for all boards, correct? W = Fd (disregarding angle of net force), distance changes, whereas the force stays the same - at least, I'm assuming the force is applied at 0 degrees.
Click to expand...

Dude, you are thinking too hard. The amount of work will ALWAYS be the same if the height is always the same neglecting friction. If the angle is lower, the amount of work per unit time decreases, but the total time goes up inversly to the amount of work being performed per unit time.
Click to expand...
But distance doesn't stay the same? 😕
 
The distance that's being talked about is the distance parallel to the force acting against you, in this case gravity. As such, the height you move it is the "d" not how far you move on the board.

Edit: That's why additional work is done if there's friction, because that work is done parallel to the friction.
 
Originally posted by: Howard
Originally posted by: Evadman
Dude, you are thinking too hard. The amount of work will ALWAYS be the same if the height is always the same neglecting friction. If the angle is lower, the amount of work per unit time decreases, but the total time goes up inversly to the amount of work being performed per unit time.
Click to expand...
But distance doesn't stay the same? 😕
Click to expand...

The only distance that matters is the vertical distance. It WOULD matter if we were taking friction into account. If we were extra work would have to be done to overcome friction. The lower the angle, the more work would have to be done to overcome friction.
 
mass*grav.*h @ lower height + (work - friction loss) = mass*grav.*height @ higher height

Conservation of energy -- mechanical potential energy is a state function wrt to some reference; it doesn't matter how you got there (i.e. angle of slope). In the case of frictionless- mech. reversible system the work to get a 'specified mass' from height A to height B is constant, independent of path.

So you could raise the mass from A to C (higher than B) and back down to B and the work would be the same. I.E. work was required to get the mass to C, then the mass did work back to the system (mechanical arm or whatever) in traveling from C to B.

In reality of course, nothing is mechanically reversible or frictionless but in some cases these are goo enough approximations...that where the real brains comes in...knowing what approximations are cool and what approx. are bullsh!t.

cheers!
 
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