# Acceleration/deceleration problem

1. Jan 25, 2005

### Gogsey

If a ball is rolled up a ramp at initial velocity 12 m/s and decelerates at a rate of 2 m/s2, then does the ball run back down the ramp with an acceleration equal to the deceleration?

The incline is 36 m long and it takes 6 seconds to reach the position where the final velocity is zero.

2. Jan 25, 2005

### quasar987

What would you say? First of all, what is the force that is the cause of the deceleration of the block?

3. Jan 25, 2005

### Gogsey

Well, its gravity that causes the deccelration up the ramp, so i would think its gravity that causes the acceleration down the ramp too, but i'm not 100% sure(mostly though).

4. Jan 25, 2005

### Gokul43201

Staff Emeritus
Since there is no mention of friction, one must assume that gravity is the only force involved that can cause the deceleration of the ball. Remember, there is one more force, but it only acts normal (perpendicular) to the inclined plane.

So, yes, the acceleration downslope should equal the deceleration upslope.

5. Jan 26, 2005

### quasar987

That is indeed correct.

IMO, the exercice was only intended to make you realize that 'deceleration' is only a word for "acceleration that slows down the speed".