Energy - practice problems - page 2 of 10
Number of problems found: 197
- Airplane mechanical energy
An airplane weighing 100 tons flies at an altitude of 11 km at a speed of 850 km/h. What is its kinetic, potential, and total mechanical energy? - Water temperature cooling
We have 160 L of water at 67°C; how many liters of cold water at 18°C are needed to cool it to 39°C? - Hammer nail force
A hammer with a mass of 600 g hits the head of a nail at a speed of 5 m/s. If the nail penetrates 3 cm into the wall, what is the average resistive force of the masonry? - Battering ram force
A battering ram weighing 400 g falls from a height of 3 m. Upon impact, the stake hits a depth of 60 cm. What is the average force overcoming the soil resistance? - Man train energy
A man with a mass of 80 kg crosses at a speed of 5 m/s through the car of a train traveling at 15 m/s. Indeed, the kinetic energy of a man: and, concerning the car b, relative to the surface of the earth, if the man is traveling in the direction of travel - Car kinetic energy
Determine the kinetic energy of a car with a mass of 800 kg if it travels at a speed: a) 10 m/s b) 20 m/s - Body kinetic work
What work must be done to bring a body of mass of 2 kg lying on a smooth horizontal plane from rest to a speed of 2 m/s? - Stone kinetic energy
What is the kinetic energy of a stone weighing 1 kg that falls in free fall 5 seconds from the start of its motion? g= 10m/s squared. - Current thermal energy
How long will it take for a current of 8A in a resistance of 30 ohms to develop thermal energy of 3 MJ if the efficiency of converting electrical energy into heat is 90%? - Office cable cross-section
In the office will be connected: computer 800 W, kettle 2.5 kW, lighting 650 W, oven 1.9 kW; electric stove 3.3 kW; air conditioning 6100 W. As the smallest cross-section of the cables, we have to bring them to this room. Recalculate for Copper and Alumin - Thermal energy
From the formula for calculating thermal energy Q=m*c*t, express t and calculate by how many °C 2kg of water must be heated to increase its energy by 126kJ - Cyclist resistance work
A cyclist rides along a horizontal path at a constant speed, overcoming a total resistance force of 20 N. What work does he do on a 5 km track? - Body trajectory energy
A body of mass 4g is shot perpendicularly from the ground and lands in 8s. What is its kinetic energy at the beginning of its trajectory, what speed does it take off, and where does the distance from the ground stop? Thank you - Car consumption average The car consumes up to 16 l in the city, but on a longer trip, the consumption drops to 10 l? 500 km per month in the city and 1650 km outside the city. What is the consumption of a car per 100 km?
- Ball collision speed
Two inelastic/plastic balls move towards each other with equal velocities of 2 m/s. The weight of one ball is 3kg, the other 1kg. Determine the speed of the balls after the collision and the loss of kinetic energy. - Flywheel energy decrease
How much energy was supplied by the flywheel of the device if its number of revolutions decreased from 1200 to 720 revolutions per minute if it has a moment of inertia of 71.3 kg/m²? - Tin body mass
The tin body transferred 150,000 J of heat, and its temperature dropped by 10°C. Calculate the mass of the tin body. (c of tin is 0.227 kJ/kg. °C). Enter the resulting weight in grams and round it to two decimal places. - Iron key temperature
By how much °C will the temperature of an iron key weighing 0.004 t change if it receives 360,000 J of heat? ( c of iron is 450 J/kg.°C ) - Steel heat capacity Calculate the mass heat capacity of a steel body weighing 2 kg, which was heated from an initial temperature of 15°C to 80°C by supplying 60 kJ of heat.
- Copper cylinder cooling
A copper cylinder weighing 15 kg transferred 114.9 kJ of heat to the surroundings during cooling. By how many degrees Celsius did it cool down?
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