A car travels at a constant speed around a circular track whose radius is 2.6 km. The car goes once around the track in 360 s. What is the magnitude of the centripetal acceleration of the car?

When I do the first calculation of 2Pi(2.6)/(360), I get .0454 for V. But when I try a=(.0454)^2/ (.0026) it only comes out right if I use .0026, not the same 2.6 I used in the first equation. Why is this? I thought they BOTH should be .0026 because I would be converting into meters.

Question

A car travels at a constant speed around a circular track whose radius is 2.6 km. The car goes once around the track in 360 s. What is the magnitude of the centripetal acceleration of the car?

When I do the first calculation of 2Pi(2.6)/(360), I get .0454 for V. But when I try a=(.0454)^2/ (.0026) it only comes out right if I use .0026, not the same 2.6 I used in the first equation. Why is this? I thought they BOTH should be .0026 because I would be converting into meters.

anonymous · Answer

2.6 km is equal to 2600 m.., so 

a = (.0454)^2/ (2600)

anonymous · Answer

well the problem is that maybe the answer is given in m/s^2 and the answer you are calculating is in km/s^2. Thus the difference of 1000.

A word of advice: always use SI system unless stated to solve problems as most books nowadays follow that system.