how can an object slow down yet have a positive acceleration?

Question

Also, how can an object that is speeding up have a negative acceleration?

Give an example of both please...thank you!!!

Answer 1

Its all in how you define your coordinate system. If you use the most common one, +ve x to the right and +ve y up, then

Say you're moving in the -ve x direction. (To the left) but your speed is getting faster. Your acceleration is still negative.

The converse is true when you are slowing down in the -ve direction. You have a positive acceleration.

Answer 2

turning. An object's tangential velocity could either be constant, slowing down or speeding up. But if there is a change in the direction of motion, there is an acceleration in the direction of the radius of curvature of the change in velocity. Changing direction is always considered a positive acceleration one way or the other.

Answer 3

the only way that can happen is if your traveling in a -ve direction. So set up a coordinate system and say that your going left (negative) then say you accelerate to the right (+ve). That way you slow down in the negative direction.

Just reverse this for the other case

Answer 4

we are talking about that in IPC but when you accelerate can have a negative accelartaion but the object has to slow down.... NOT SPEED UP... ( that question was on my test today) so like ya..

Answer 5

v=@t+vo so if vo is negative(remember velocity is a vector)
v can be negative
@=4m/s^2 and vo=-20m/s
The initial speed is 20m/s and at t=5s the speed is 0
2) @=-4m/s^2 (acceleration is also a vector) and vo=-20m/s
v=-4t-20
at t= 0 the speed is 20m/s and at t=5s the speed is 40m/s

Answer 6

isnt that impossible?!
how can a positive be a negative...
so that means its getting faster but its also decelerating at the same time?

umm..ok, i was like of no use but could the answer be
it cant? [=

Answer 7

It's all relative to your reference point.