A 1300 kg sports car accelerates from rest to 90 km/h in 7.4 s. What is the average power delivered by the engine?
4635.12J
To find the average power delivered by the engine, we can use the formula:
Average Power = work/time
First, let's convert the given speed from km/h to m/s:
90 km/h = (90 * 1000) m / (60 * 60) s = 25 m/s
Now, let's find the work done by the car to accelerate from rest to 90 km/h. The work done can be calculated using the formula:
Work = (1/2) * mass * velocity^2
Work = (1/2) * 1300 kg * (25 m/s)^2 = 406,250 J
Since work is equal to the average power multiplied by the time, we can rearrange the formula to solve for average power:
Average Power = Work / time
Average Power = 406,250 J / 7.4 s ≈ 54,901 W
Therefore, the average power delivered by the engine is approximately 54,901 Watts.
To find the average power delivered by the engine, we can use the formula:
Power = Work / Time
First, let's calculate the work done by the engine. The work done is equal to the change in kinetic energy (ΔKE) of the car:
ΔKE = (1/2) * m * (v^2 - u^2)
where m is the mass of the car (1300 kg), v is the final velocity (90 km/h or 25 m/s), and u is the initial velocity (0 m/s since the car starts from rest).
ΔKE = (1/2) * 1300 kg * (25 m/s)^2 = 812,500 J
Next, we need to find the time taken to reach the final velocity. The time given in the problem is 7.4 s.
Finally, we can calculate the average power delivered by the engine:
Power = 812,500 J / 7.4 s = 109,864.86 W
Therefore, the average power delivered by the engine is approximately 109,864.86 Watts.
P=W/t
Must use standard units : N m s
1400kg*9.8=13720N
90km/h = 9000m/3600s = 2.5m/s
13720N(2.5m/s)/7.4s
4635.12J