A motorcyclist overcomes a horizontal section moving at a speed of 120 km / h if the friction force acting
| August 5, 2021 | education
A motorcyclist overcomes a horizontal section moving at a speed of 120 km / h if the friction force acting on the motorcycle is 1.2 kN, then what power (in kW) the engine develops at this moment.
V = 120 km / h = 33.3 m / s.
Ftr = 1.2 kN = 1200 N.
N -?
Power N is a physical quantity that shows the speed of work and is determined by the formula: N = A / t, where A is the work of the engine thrust force F, t is the time of its execution.
A = F * S.
Since the motorcyclist moves uniformly, the traction force F is compensated by the friction force Ffr, according to 1 Newton’s law.
The speed of movement is determined by the formula: V = S / t.
N = Ftr * S / t = Ftr * V.
N = 1200 N * 33.3 m / s = 39960 W.
Answer: the motor has a power of N = 39960 W.
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