Centripetal acceleration problem (very easy)

[coding_delight]

A 2.5 kg object moves at a constant speed of 8.0 m/s in a 5.0 m radius circle. What is the object's acceleration?

I'm quite sure the answer to the problem is 32 m/s^2, but apparently the right answer is 13 m/s^2. Unless I'm missing a detail about the "constant velocity" part of the problem, can some one please explain why the answer is 13.

 

[Danger]

Welcome to PF, Coding... but you're in the wrong forum. This is pretty obviously a homework question, which is not allowed in this section. As such, you must show what you've already done by way of figuring it out.

 

[bel]

$$a_c= \frac{v^2}{r}$$

The mass is superfluous.

 

[HallsofIvy]

A 2.5 kg object moves at a constant speed of 8.0 m/s in a 5.0 m radius circle. What is the object's acceleration?

I'm quite sure the answer to the problem is 32 m/s^2, but apparently the right answer is 13 m/s^2. Unless I'm missing a detail about the "constant velocity" part of the problem, can some one please explain why the answer is 13.

How could you possibly have got "32 m/s^2"? The only way to combine the numbers given to get 32 would be "8² times 2.5 divided by 5". If you do that, your units would be kg m/s², not m/s². Since there is no mass unit in acceleration, as bel says, the mass is irrelevant.

 

[ank_gl]

duh.. 32 units is the force, 13units is the acceleration

 

[rsamudrala]

A 2.5 kg object moves at a constant speed of 8.0 m/s in a 5.0 m radius circle. What is the object's acceleration?

I'm quite sure the answer to the problem is 32 m/s^2, but apparently the right answer is 13 m/s^2. Unless I'm missing a detail about the "constant velocity" part of the problem, can some one please explain why the answer is 13.

acceleration = v*v/r
= 8*8/5
= 64/5=12.8
= 13 (approx)