Fundamentals of Physics + power - practice problems - page 3 of 4
Number of problems found: 64
- Friction coefficient
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 - 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? - Performance 7737
Zdenek, weighing 54 kg, made 15 push-ups on the crossbar. The height he reached was about 40 cm. What kind of work did he do? What was his performance if the whole exercise took him a minute and a half? - Temperature 7595
Colorless liquid weighing m = 200 g is heated with constant stirring on a stove with power input P0 = 600W. 80% of the supplied energy is used to heat the liquid. Selected measured values of liquid temperature as a function of time are recorded in the t
- Resistance 7503
The resistance of a 40W light bulb is 10 Ohms. What voltage source is connected to it? What current is flowing through it? - Orlík hydroelectric plant
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 pow - A car
A car weighing 1.05 tonnes driving at the maximum allowed speed in the village (50 km/h) hit a solid concrete bulkhead. Calculate height would have to fall on the concrete surface to make the impact intensity the same as in the first case! - Acceleration 7054
The car brakes with an acceleration of 5 m/s-2. Determine the stopping distance of the car if its initial speed is a) 54 km/h, b) 108 km/h. Compare the calculated braking distances concerning the given speeds. - Seawater
Seawater density is 1025 kg/m³, and ice is 920 kg/m³. Eight liters of seawater froze and created a cube. Calculate the size of the cube edge.
- Electricity 6667
A light bulb with power consumption P = 70 W. It is connected to a mains voltage of 230 V. How big is the electric current that flows through it? How much electricity in kWh will it use if it is on for 9 hours 30 minutes? - Consumption 6581
We heated water weighing 1 kg at 70 degrees in a kettle. C. In 5 min. What is the power consumption of the kettle? We do not take into account losses or boiling points. - Resistance - ohms
If the resistance of the first resistor is 300 ohms and the resistance of the second resistor is 100 ohms. What is the resulting resistance? - Electric 5914
A current of 2 A at a voltage of 400 V passes through the electric motor. The electric motor is switched on for 0.5 h. What is the power input of the electric motor? - The appliance
The appliance has a power input of 2.3 kW. It is connected to the mains voltage of 230 V. What is the current flowing through the appliance?
- Electrical 5720
The bulb is connected to a 4.5 V power supply. An electric current of 45 mA flows through the filament of the bulb. The calculated size of the electrical field of the filament lamp - Tower model
The tower's height is 300 meters, and its weight is 8000 tons. How high is the model of the tower's weight of 1 kg? (State the result in centimeters). The model is made from exactly the same material as the original no numbers need to be rounded. A result - Efficiency 4073
Determine the efficiency of a vacuum cleaner with a power input of 1.2 kW when the suction power is 360 W. - Efficiency
What is the power output of a kettle 2 kW with an efficiency of 90%? - Hollow sphere
The steel hollow sphere floats on the water plunged into half its volume. Determine the outer radius of the sphere and wall thickness, if you know that the weight of the sphere is 0.5 kg and the density of steel is 7850 kg/m³
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