# Speed v Velocity v Acceleration

1. Jan 31, 2007

### future_vet

I think it's a shame that in everyday language we confuse velocity and speed so easily. It makes it much more confusing to know the difference...

Can an object have increasing speed but have a decreasing acceleration at the same time?

When we go around something, and end up where we started, is our average velocity 0?

Thanks!

2. Jan 31, 2007

### denverdoc

to the first question:

sure it happens many times I fly my rockets. In other words as the rocket motor hits its peak thrust and begins to subside, two things are happening:

the upward acceleration due to the motor thrust is diminishing, but the acceleration is still positive and so it must be gaining velocity except,

the faster it flies, the greater the air resistance which robs from the thrust.

So there are also times when the motor is still generating thrust but the drag forces or so high, that it is decelerating.

Second question absolutely since velocity is defined by displacement/time,
net displacement zero, velocity zero.

3. Jan 31, 2007

### future_vet

Thanks a lot!