Power input

The construction lift lifted a load weighing 300 kg to a height of 12 m with a uniform movement. How long has it taken for the load to be lifted if the efficiency is 75% and the engine has a power input of 5 kW?

Correct answer:

t =  9.6 s

Step-by-step explanation:

P=5 kW W=5 1000  W=5000 W ξ=75%=75100=0.75 V=ξ P=0.75 5000=3750 W  m=300 kg h=12 m  g=10 m/s2  F=m g=300 10=3000 N  W=F h=3000 12=36000 J  t=W/V=36000/3750=9.6 s



Did you find an error or inaccuracy? Feel free to write us. Thank you!






avatar




Tips to related online calculators
Our percentage calculator will help you quickly calculate various typical tasks with percentages.
Do you want to convert mass units?
Do you want to convert time units like minutes to seconds?

You need to know the following knowledge to solve this word math problem:

Related math problems and questions:

  • Elevator
    vytah-sachta In homes with more floor elevators are used. For passenger transport, the most commonly used traction elevator counterweight. The top of the shaft engine room with the engine. The car is suspended on a rope, which is guided up over two pulleys to the coun
  • Electric cooker
     electric cooker During which time t does an electric cooker with power input P = 500 W and with efficiency n = 75% heat water with mass m = 2 kg and temperature t1 = 10°C to the boiling point (t2 = 100°C). The specific heat capacity of water is c = 4 180 J. Kg-1. K-1
  • Efficiency
    rychlovarna-kanvica What is the power output of kettle 2 kW with efficiency 90%?
  • Car
    motor_cylinders_kW At what horizontal distance reaches the car weight m = 753 kg speed v = 74 km/h when the car engine develops a tensile force F = 3061 N. (Neglect resistance of the environment.)
  • Concrete column
    beton The concrete column of the highway bridge has the shape of a block with dimensions of 1m x 0.8m x 25m. It should be lifted by crane to a height of 20m. What is the power of his engine if the lifting takes 2 minutes?
  • Orlík hydroelectric plant
    1280px-Orlík The Orlík hydroelectric power plant, built in 1954-1961, consists of four Kaplan turbines. For each of them, the water with a flow rate of Q = 150 m3/s is supplied with a flow rate of h = 70.5 m at full power. a) What is the total installed power of the p
  • Weightlifter
    culturist Weightlifter lifted 75% of its weight. Determine how much weight lifted when he weighs 132 kg.
  • Friction coefficient
    car What is the weight of a car when it moves on a horizontal road at a speed of v = 50 km/h at engine power P = 7 kW? The friction coefficient is 0.07
  • Motor physics
    car_motor A car is traveling at 98 km/h on the highway. The pulling power of the motor is 6 kN. Find the engine power in kW.
  • Positional energy
    energy What velocity in km/h must a body weighing 60 kg have for its kinetic energy to be the same as its positional energy at the height 50 m?
  • Inclined plane
    naklonena_rovina 1. How much work W we have to do to pull a body weighing 200 kg along an inclined plane with a length of 4 m to a total height of 1.5 m. 2. Find the force we need to exert to do this if we neglect frictional resistance. 3. Find the force we would need if
  • Motorcycle engine
    motor_rpm The motorcycle engine has a constant power of 1.2 kW for 0.5 hours. How much work does the engine do? Express work in kWh and Ws units.
  • The elevator
    lift-gear-motor-250x250 The elevator car weighing 400 kg rises from the third to the fifth floor. By what value will the potential gravitational energy of the cabin increase? What useful work will the elevator motor do? The height of one floor is 5m .
  • Free fall
    freefall1 The elevator car weighing 720 kg is torn off at a height of 125 m and begins to fall in a free fall. How much kinetic energy does the elevator car have when it hits the ground floor of the building, when the free fall of the car lasted 5 s?
  • BMI index
    man_BMI Calculate BMI (body mass index, an index indicating obesity, overweight, normal weight, underweight) man weighing m = 71 kg and height h = 170 cm. The index is calculated according to equation (formula): BMI = (m)/(h2) With BMI index is possible to compa
  • Gasoline
    fuel_pump2 How many liters of gas is in the tank if its weight 15.4kg. Specific density of gasoline is 770kg/m3.
  • Chained winch
    vedro When digging a well, a chained winch is used to balance the material. An empty shackle weighs 8 kg, a full 64 kg. What force must the worker exert on the crank handle when pulling the shackle with a uniform movement from a depth of 5 m if the shaft diamet