# Pull, or tension

1. Oct 3, 2009

### yyttr2

You have a toy car on a table and a single pulley on the end. You tie a string to the car, and the other end to some 20 gram weights next put the string on the single pulley.
The force causing the car to accelerate when you let it go is it Fp or Ft
(pull force or tension)

Last edited: Oct 3, 2009
2. Oct 3, 2009

### sleventh

the force of gravity causes the car to move. but the force will be in the form of tension since that is the only things connecting your weight to the car.

3. Oct 3, 2009

### yyttr2

Reason I asked, because someone told me it was a pull force (because the rope is pulling on the car) when I thought it was tension...thanks

4. Oct 4, 2009

### Cleonis

It seems to me your question is about language rather than physics.

- I would use the word 'tension' to refer to what is happening inside the string. Along the length the fibers of the string are under tension.
- I would use the word 'pull' to refer to the force that the string exerts upon the car. Gravity pulls on the string, the string pulls on the car.
But that's just my personal preference in how I would use those words.

Assuming the string and the pulley can be thought of as frictionless and massless, the tension and the pull will be equal in strength.

Cleonis