Energy - practice problems - page 7 of 10
Number of problems found: 196
- Weighing 12471
Compare the kinetic energy of a man weighing 80 kg who runs at a speed of 2 m/s and missiles weighing 20 g fired at 400 m/s. - Determine 12461
The 150t aircraft takes off at a speed of 288km/h and, after a while, reaches a speed of 900km/h. Determine the change in the kinetic energy of the aircraft. - Kinetic energy A car traveling at a speed of 25 km/h increased the speed to a) 75 km/h b) 100 km/h when exiting the highway. How many times has its kinetic energy increased?
- Potential 12431 From what height does a hammer weighing 200 kg fall if its initial potential gravity was 6 kJ?
- The elevator
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. - Gravitational 12411 We lift a weight of 2 kg to a height of 50 cm above the top of the table. Determine its gravitational potential energy: a) relative to the tabletop, b) relative to the floor if the table top is 1m above the floor.
- Positional 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 of 50 m?
- Horizontally 11211
A boy weighing 50 kg moves horizontally by 10 m. What is his kinetic energy at a speed of 1 m/s? - Horizontally 11201 A boy weighing 50 kg moves horizontally by 10 m. How much has his positioning energy increased?
- 3 phase load
Two wattmeters are connected to measure power in a 3 phase balanced load. Determine the total power and power factor if the two wattmeters read 1000 watts each (1) both positive and (2) the second reading is negative. - Kilowatt-hours
If the Lewis family used 648 kilowatt-hours of electricity in 12 days at the same usage rate, how many kilowatt-hours should they use in 24 days? - 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 - 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?
- 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 would have been his performance if the whole exercise had taken 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 - Gasoline price
At 34.4 cents per liter, how much will 42 liters of gasoline cost? - 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? - Temperature 7477
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.
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