Total force resisting the forward motion of a boat at a speed

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SUMMARY

The total force resisting the forward motion of a boat powered by a 100 kW engine at a speed of 70.0 km/h can be calculated using the relationship between power, force, and velocity. At maximum velocity, the engine's power output equals the resisting power of the water. The equation for power, P = F * v, where P is power, F is force, and v is velocity, is essential for this calculation. Thus, the total resisting force can be determined by rearranging the equation to F = P / v.

PREREQUISITES
  • Understanding of basic physics concepts such as force, power, and velocity.
  • Familiarity with the equation P = F * v.
  • Knowledge of unit conversions, particularly between kW and N·m/s.
  • Basic problem-solving skills in physics.
NEXT STEPS
  • Calculate the total resisting force using the formula F = P / v with P = 100 kW and v = 70.0 km/h.
  • Explore the implications of water resistance on boat design and performance.
  • Research the effects of different hull shapes on resistance and speed.
  • Learn about the principles of fluid dynamics as they relate to marine engineering.
USEFUL FOR

Marine engineers, physics students, boat designers, and anyone interested in understanding the dynamics of boat propulsion and resistance.

sparkle123
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Problem:
A boat powered by an engine rated at 100 kW can reach a top speed of 70.0 km/h. What is the total force resisting the forward motion of the boat at this speed?

I don't know which equations to use :(
 
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Well if I am correct, then at that max velocity the engine is using all of its 100kW of power to maintain that speed. So you know that to maintain constant velocity the power output of the engine must be equal to the resisting power of the water.

Now if the work done over any distance 'x' by the water is F*x, then what is the power?
 
Got it! Thanks for your help!
 

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