- #1
stfz
- 35
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Hi,
I am taking a high school physics course, and there are a few points at which I am getting a bit of confusion.
My first area of confusion relates to Newton's Laws. There are a few scenarios in which I am not clear as to the interaction of forces, etc.
a) Exactly why does putting wheels/rollers/etc under a heavy object make it easier to move?
since force due to friction is : f = u*Fn, where u is the coefficient of friction, Fn is weight.
Looks like force due to friction is dependent only on weight and the coefficient of friction, not surface area which is in contact. What exactly makes it easier? Or is coefficient of friction dependent on surface area?
b) Is the definition of Work (Work (Joules) = Force * distance, Joules = Newton * m) supposed to be intuitive? Since I don't really understand how "work" is defined in that way. I can work with the definition, but it's just that I cannot REALLY understand why it is so.
Definition of work is : W = F * Δx, F = force, Δx = Distance. I just want to clarify this :
Assuming a zero-friction environment, if I push an object with constant force, the object will continually accelerate.
In order to produce work with an object for n meters, then, I assume I will need to push the object continually with constant force. This means I will have to keep going faster and faster. Is that right?
My textbook has this question : "A refrigerator repairman pushes a refrigerator 75 cm horizontally to get access to the panel behind it. If the worker pushed horizontally and did 175 Joules of work, with what force did he push?".
I assume that in this question, ignoring friction, then, that the repairman would have to push the fridge with constant force, thus giving it increasing velocity?
I'm sorry if this seems overly basic... my book did not explain this very concisely.
Would appreciate any input :)
Thanks!
Stephen
I am taking a high school physics course, and there are a few points at which I am getting a bit of confusion.
My first area of confusion relates to Newton's Laws. There are a few scenarios in which I am not clear as to the interaction of forces, etc.
a) Exactly why does putting wheels/rollers/etc under a heavy object make it easier to move?
since force due to friction is : f = u*Fn, where u is the coefficient of friction, Fn is weight.
Looks like force due to friction is dependent only on weight and the coefficient of friction, not surface area which is in contact. What exactly makes it easier? Or is coefficient of friction dependent on surface area?
b) Is the definition of Work (Work (Joules) = Force * distance, Joules = Newton * m) supposed to be intuitive? Since I don't really understand how "work" is defined in that way. I can work with the definition, but it's just that I cannot REALLY understand why it is so.
Definition of work is : W = F * Δx, F = force, Δx = Distance. I just want to clarify this :
Assuming a zero-friction environment, if I push an object with constant force, the object will continually accelerate.
In order to produce work with an object for n meters, then, I assume I will need to push the object continually with constant force. This means I will have to keep going faster and faster. Is that right?
My textbook has this question : "A refrigerator repairman pushes a refrigerator 75 cm horizontally to get access to the panel behind it. If the worker pushed horizontally and did 175 Joules of work, with what force did he push?".
I assume that in this question, ignoring friction, then, that the repairman would have to push the fridge with constant force, thus giving it increasing velocity?
I'm sorry if this seems overly basic... my book did not explain this very concisely.
Would appreciate any input :)
Thanks!
Stephen