Energy - practice problems - page 8 of 11

Number of problems found: 207

Calories 2
Ben eats approximately 2400 calories per day. His wife Sarah eats 5/8 as much. How many calories does Sarah eat per day?
Power input
The construction lift lifted a 300 kg load to a height of 12 m with uniform movement. If the efficiency is 75% and the engine has a power input of 5 kW, how long did it take for the load to be lifted?
Workers - earning
Twelve workers would earn € 800 in 10 days. How many euros would 14 workers earn in 8 days?
Push-up work calculation
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 would have been his performance if the whole exercise had taken him a minute and a half?
Heating Liquid Graph Analysis
Colorless liquid weighing m = 200 g is heated with constant stirring on a stove with power input P0 = 600 W. 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 ta
Gasoline price
At 34.4 cents per liter, how much will 42 liters of gasoline cost?
Light bulb resistance
The resistance of a 40 W light bulb is 10 Ohms. What voltage source is connected to it? What current is flowing through it?
Temperature and volume
The pool with a length of l = 50 m and a width of s = 15 m has a depth of h1 = 1.2 m at the shallowest part of the wall. The depth then gradually increases to a depth of h2 = 1.5 m in the middle of the pool. = 4.5 m walls in the deepest part of the pool.
The tub
If we drop the 5 l from the first tap and the second 2 liters of water, the water in the tub will have a temperature of 25°C. If we drop 3 l from the first tap and from the second 4 l of water, the water in the tub will have a temperature of 21°C. Determi
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 power of the p
Electric input power
Solve problems related to electric power: a) U = 120 V, I = 0.5 A, P =? b) P = 200 W, U = 230 V, I =? c) I = 5 A, P = 2200 W, U =?
Bulb 4
In an electric circuit, a bulb (4.5 V, 0.1 A) and a resistor with resistance 45 Ω are connected to a 4.5 V voltage source. Will the bulb shine at full brightness in this circuit? Support your answer with calculations, and possibly look for solutions so th
Electricity consumption
Calculate how much we will pay for 1 hour of consumed electrical energy if the seller sets a price of 0.126 euros for 1 kWh (all appliances together for 1 hour of work). Table: Appliance ; Power (W) Washing machine ; 2300 W Bulb ; 40 W Refrigerator; 200 W
Bulbs and electricity
In the sports hall, 875 identical light bulbs are on for 2 hours. How long would 100 such light bulbs need to be on to consume the same amount of electricity?
Light Bulb Power Electricity Usage
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?
The bulb
Calculate the voltage at the bulb's terminals; if the work 18 J is done to transfer particles with an electric charge of 6 C.
Kettle Power Consumption
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.
Water mixing
How many liters of hot water at 80 °C do we have to mix with water at 10 °C to get 10 liters of warm water at 45 °C?
Electricity Consumption Reduction
In two months, the Novák family consumed 624 kWh of electricity during the day and 3018 kWh at night. How much kWh of electricity will the Novák family consume now in two months at the daily rate, and how much at the night rate if they decide to reduce co
Electric energy
There are 875 identical light bulbs in the sports hall lighting for 2 hours. How long does the same amount of electricity consume 100 such bulbs?

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