## soccergal12 3 years ago explain whether or not a particle would have acceleration if (a) it's moving in a straight line with constant speed, and (b) moving around a curve with constant speed

1. CliffSedge

What does it mean for something to accelerate? What has to change?

2. soccergal12

velocity ?

3. MuH4hA

Correct. And in which of the 2 cases does the velocity change? (Remember that velocity is a vector quantity meaning you have to take into account the speed _and_ the direction)

4. sagarrobo

if it is moving on astright line it has no acc for constant speed if along a curve then it has centripetal acceleration toward the centre of curve

5. soccergal12

the velocity changes in the second case

6. sagarrobo

yes it changes but not he magnitude but its direction and since it is a vector quantity so if direction changes evevn if magnitude is constant then also it changes

7. soccergal12

so the direction changes, but magnitude doesn't? therefore, since direction changes, there's also a change in acceleration?

8. sagarrobo

yes definitly

9. soccergal12

okay, thank you!

10. chongkhengwye

Acceleration is the rate of change of velocity. In (a), it is possible there is an acceleration if the object suddenly moves in the opposite direction in a small time of t; i.e. a = 2*v/t In (b), for the object to move in a curve, the direction of its motion must be changing all the time, and thus its velocity changes, leading to non-zero acceleration.