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This is (what seems to me) an old question people have been playing with for a while, but I dont seem to be able to figure out where I have gone wrong.

Could someone point out the mistake in my math from the following example:

Constant Mass = 1180Kg

Sample 1 @ 2 secs

Kilometers/Hour = 37

Meters/Sec = 10.278

RPM = 3000

Sample 2 @ 3 secs

Kilometers/Hour = 46

Meters/Sec = 12.778

RPM = 3780

Sample 3 @ 4 secs

Kilometers/Hour = 59

Meters/Sec = 16.389

RPM = 4860

Using the formula: KE = (1/2)(m)(v^2) I calculated

KE1 = 0.5 * 1180 * (10.278 * 10.278) = 62326 ??Joules??

KE2 = 0.5 * 1180 * (12.778 * 12.778) = 96333.6 ??Joules??

KE3 = 0.5 * 1180 * (16.389 * 16.389) = 158473.6 ??Joules??

Using the formula: W = (KE / Time) given the sampling time is 1sec

W = KE.

Converting (roughly) from W (watts) to HP: HP = W / 746

HP1 = 83.54

HP2 = 129.12

HP3 = 212.32

I know from another piece of software that the correct values should be:

HP1 = 59

HP2 = 76

HP3 = 105

Could someone be kind enough to point out my fault. Greatly appreciated.

Tony

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# Homework Help: Calculating Horsepower/Torque from Acceleration/Mass

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