Fundamentals of Physics - practice for 14 year olds - page 11 of 20
Number of problems found: 388
- Electric 25011
How much voltage do we measure on a 400Ω resistor when an electric current of 55 mA passes through it? - Copper Cu wire
Copper wire with a diameter of 1 mm and a weight of 350 g is wound on a spool. Calculate its length if the copper density is p = 8.9 g/cm cubic. - Determine 23741
Adam and Eve live 20 km apart. They are going to a meeting. Adam moves at a speed of 2 km/h faster than Eva. They will meet in one and a half hours. Determine their speeds. - The coal
The coal stock would be enough to heat a larger room for 12 weeks and a smaller one for 18 weeks. It was heated for four weeks in both rooms, then only in a smaller one. How long was the coal stock enough?
- Temperature 22861
The small bulb's socket has a reading of 6.3V/0.3A, which applies to its filament when the bulb is on. Determine the electrical resistance of the fiber under the given condition (the temperature of the fiber corresponds to about 2800°C) - Short-circuit 22841
An external circuit with a resistance of 3.8 Ω is connected to an electrical voltage source with Ue=12 V. A current of 3 A passes through the circuit. Specify: source terminal voltage, the internal resistance of the source, maximum short-circuit current. - Approximately 22253
The water in the container has a temperature of t1 = 80◦C, the temperature around the container is t2 = 15◦C. The dependence of temperature t on time τ (in minutes) can be expressed approximately by the formula: t = t2 +(t1 −t2)·e^(−0.05·τ) Calculate the - Movement 21953
We lift a box weighing 50 kg onto a railway wagon with a precise movement along a 3m track. We will use a fixed pulley. What is the pulling force on the free end of the rope? - Cooker
A current of 2A passes through the immersion cooker at a voltage of 230V. What work do the electric field forces do in 2 minutes?
- Distance 21883
The distance between K and L is 150 km. At 8.00, a car left place K at a speed of 60 km/h. At 9:00 a.m., a second car drove towards him from location L at 75 km/h. At what time will they meet, and how far from L will it be? - Length 21863
The steel wire (α = 11.5. 10-6 K-1) has a length of 100 m at -15 °C. Find its length at 45 °C. - The copper wire
The copper wire bundle with a diameter of 2.8mm weighs 5kg. How many meters of wire are bundled if 1m³ of copper weighs 8930kg? - The shooter
The shooter heard the bullet's impact on the target one second after the shot. The bullet was moving at an average speed of 500 m/s. Calculate with the speed of sound of 340 m/s. Determine the distance of the target. - Automatically 20853
Please calculate according to Pascal's law. The depth bomb used against the submarine was equipped with a hydrostat, which automatically caused it to explode at a given depth. The hydrostat was set to a pressure of 400kPa. At what depth below the surface
- Motorcyclist 20473
The cyclist leaves place A at a speed of 25 km/h. A motorcyclist rides against him at a speed of 55 km/h. The distance between places A and B is 60 km. When and where do I meet? - Transformer 20073
The transformer is oil-cooled and transforms a power of 20MW with an efficiency of 92%. Determine the temperature of the oil at the outlet of the transformer if the oil was 20°C when it entered the transformer. 2.5 liters of oil will flow through the tran - Oscillation 17313
The period of the natural oscillation of the railway car is 1.25s. The length of the rails is 25 m. At what speed does the vibration, caused by the impact of the wheels on the joints between the rails, reach a maximum? Give the result in m/s. - Self-oscillation period
The water in the vessel carried by the boy has a self-oscillation period of 0.8 s. What is the size of the boy's movement speed when the length of the boy's step is 60 cm? Give the result in m/s. - Water mixing
We mix 2 liters of water at 100 degrees Celsius warm and 18 liters of water at 32 degrees Celsius warm. What temperature will the water have after mixing?
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