Angular acceleration, and revolution

[keylostman]

Homework Statement

A car engine accerlates from 1080rpm to 4800rpm in 12.5 seconds. Calculate the angular accleration, assumed constant, and the total number of revolutions the engine makes in this time

The Attempt at a Solution

angular acceleration (a) = (wf - wi) /(tf - ti)
(a) = (160 - 36) π / 12.5 = 31.15 rad/s^2

angle moved = θ = wi * t + 0.5 at^2
θ = 36 π *12.5 + 0.5 [124 π / 12.5 ] [12.5]^2
θ = 450 π + 0.5 [124 π] 12.5
θ = 450 π + 775 π = 1225 π
θ = [1225/2] [2π] = N[ 1 revolution]
N = numberof revolutions made = N = 1225/2 = 612.5


DID I DO THIS RIGHT?

 

[PhanthomJay]

Yes. I suppose you didn't have to convert revolutions to radians when determining the angular acceleration, that is, you could have left it in rev/sec^2, although rad/sec^2 is the standard SI unit for angular acceleartion. Looks good.

 

[Moetasim]

I cannot verify the calculations as I do not have access to the original data or equations used. However, the general approach and equations seem to be correct for calculating angular acceleration and the number of revolutions. It would be helpful to double check the calculations and units to ensure accuracy. Additionally, it is important to note any assumptions made in the calculations and whether they are valid in this scenario. Overall, the solution seems reasonable, but it is always important to verify and check for any potential errors.