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## Main Question or Discussion Point

Hi, I am a bit stuck. I am trying to work out the top speed a motorbike can reach, I have a table with bhp and torque and the highest bhp of 150 is at 9,000 rpm. I have done the following calculations:

Diameter of tyre + wheel: 0.5m

Circumfrence of tyre + wheel: 1.5707963m (round up to 1.6m)

Final drive ratio: 2.0

RPM of wheel: 9,000 / 2 = 4500 rpm

-RPM to RPS = 4500 / 60 = 75 RPS (Revs per second)

theoratical speed of motorbike = 75 x 1.6 = 120 m/s

convert that to mph = 268 mph

but I need to derive an equation to calculate the velocity taking rolling and air resistance into consideration. Now I know I need to find the Air Resistance force by using the Drag formula and rolling resistance force using the rolling resistance formula. I am thinking of using P = FV where P is the max power output at 9,000 rpm and F = Drag force + Rolling Resistance Force. I would use my theoratical speed in my drag force equation. This would give me the velocity(V) the bike can reach on the road considering the drag and air resistance force. Am I right ? I am sort of confused because I can use the kinetic energy equation as I have the mass but then should I use the max power at 9,000 rpm. I am really confused. Am I thinking of this the right way ? Also can any of you tell me what the average rolling resistance coefficient is for the tyres on a sportsbike like kawasaki ninja ? Thank you.

Diameter of tyre + wheel: 0.5m

Circumfrence of tyre + wheel: 1.5707963m (round up to 1.6m)

Final drive ratio: 2.0

RPM of wheel: 9,000 / 2 = 4500 rpm

-RPM to RPS = 4500 / 60 = 75 RPS (Revs per second)

theoratical speed of motorbike = 75 x 1.6 = 120 m/s

convert that to mph = 268 mph

but I need to derive an equation to calculate the velocity taking rolling and air resistance into consideration. Now I know I need to find the Air Resistance force by using the Drag formula and rolling resistance force using the rolling resistance formula. I am thinking of using P = FV where P is the max power output at 9,000 rpm and F = Drag force + Rolling Resistance Force. I would use my theoratical speed in my drag force equation. This would give me the velocity(V) the bike can reach on the road considering the drag and air resistance force. Am I right ? I am sort of confused because I can use the kinetic energy equation as I have the mass but then should I use the max power at 9,000 rpm. I am really confused. Am I thinking of this the right way ? Also can any of you tell me what the average rolling resistance coefficient is for the tyres on a sportsbike like kawasaki ninja ? Thank you.