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Calculation on power The rated power of the car is p. = 80kW. The resistance of the car is f = 25000n. The mass of the car is m = 2000kg. If the car starts to move in a straight line with uniform acceleration from standstill, the acceleration is a = 1m / S2. When the car reaches the rated power, it keeps the rated power unchanged and continues to drive 1. The maximum speed that the car can reach in the whole driving process The instantaneous power of the vehicle at the end of 2.20s 3. Instantaneous power when the speed of the car is 5m / s 4. Acceleration when the speed of the car is 20m / s If there is a calculation process (with formula), the result should be correct (I have the result of the answer)
When the speed is maximum, f = f = 2500n
Vmax-Vo=at
PE = F X Vmax
1.Vmax=80000/ 2500=32m/s
Vmax-Vo=at
32-0=1t t=32s
After that, they all move in a straight line at a constant speed with PO
two
V1-Vo=at1
V1=0+1x20=20m/s
F = F + Ma = 2500 + 2000x1 = 4500n
twenty
44. The rated power of a lift motor is 3.0 × 104w, of which 15% is used to overcome the friction resistance. The total weight of the movable part of the lift is 6.0 × 103n, and the average weight of each passenger is 750N. If the lift rises at a constant speed of 2.0m/s, it can carry at most several passengers
Calculation about power
The mass of a car is 5000 kg. The car starts to drive on the straight road with constant power from standstill. After 40 seconds, the speed of 400m reaches the maximum value. If the resistance of the car is always 0.05 times of the vehicle weight, the maximum speed? G is taken as 10
Resistance f = 2500n
1/2M*V^2 = PT - fS
P=f*V
2500*V^2=2500*40*V - 2500 *400
V^2-40V+400=0
(V-20)^2=0
V=20m/s
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