# Force exerted on you while you move in a circle at unchanging speed?

1. Jan 27, 2008

### subieman

Is any force exerted on you while you move in a circle at unchanging speed? howdo you know?

2. Jan 27, 2008

### Staff: Mentor

Are you accelerating? What does Newton's 2nd law tell you?

3. Jan 27, 2008

### subieman

No acceleration cuz its amoving at a contastant speed.I dont know newtons 2nd law

4. Jan 27, 2008

### Staff: Mentor

In physics, acceleration means a change in velocity, not just speed. Velocity changes when the direction of motion changes, so circular motion is accelerated.

Newton's 2nd law will tell you that force and acceleration are proportional. But even Newton's 1st law should tell you that a force is required in order for something to do anything but continue moving in a straight line at constant speed.

Imagine that you tied a rock on the end of a string and swung it around in a circle. Does that require exerting a force on the rock (via the string)? Sure.

5. Jan 27, 2008

### subieman

Ok, the rock and the string makes alot of sense. so there would be a force exerted on you because a force is required for something to do anything right?

6. Jan 27, 2008

### Staff: Mentor

A net force is required for an object to change its motion (change speed or direction).

7. Jan 27, 2008

### YellowTaxi

yep, you can be pretty sure that anything which doesn't move in a dead straight line is being accelerated by a force. It was Galileo who dicovered that simple idea.

8. Jan 27, 2008

### subieman

Thanks for the help. Its alot clearer now.