Fundamentals of Physics - practice for 14 year olds - page 10 of 19
Number of problems found: 371
- Traveling 27833
The truck drove at an average speed of 20 km/h and left Prague toward Liberec. At the same time, a bus left with him, traveling at an average speed of 30 km/h, and it arrived in Liberec 2 hours earlier than the truck. What is the distance between Prague a - Candles
Before Christmas, Eva bought two cylindrical candles - red and green. Red was 1 cm longer than green. She lit a red candle on Christmas Day at 5:30 PM, lit a green candle at 7:00 PM, and left them on fire until it burned. At 9:30 PM, both candles were the - Receiving heat
How many degrees Celsius was an iron cylinder weighing 300 g heated in a water bath if it received heat of 7.2 kJ? (specific heat capacity of iron c = 0.46kJ/kg/ºC) - Transformation 26961
The output voltage of the transformer is 880 V. The secondary coil has 1200 turns. Determine the voltage to which the primary coil is connected and how many turns it has if a current of 1 A flows through it. The transformation ratio is k = 4. What current
- Motorcycle engine
The motorcycle engine has a constant power of 1.2 kW for 0.5 hours. How much work does the engine do? Express work in kWh and Ws units. - Temperature 25901
Calculate the speed of sound in the air a) at a temperature of t = 20 °C b) at a temperature of t = 27 °C - Water mixing
We have 520 ml of hot water and 640 ml of water at 48°C. What is the temperature of approximately hot water when the resulting mixture has a temperature of 65°C? - Electric work
Calculate the work done by the electric forces passing the current of 0.2 A through the bulb in 10 minutes if the bulb is connected to a 230 V power supply. - Two resistors
Two resistors, 20 Ω, and 60 Ω, are connected in series, and an external voltage of 400 V is connected to them. What are the electrical voltages on the respective resistors? Please comment!
- Resistances 25281
Three resistors with resistances of 200 Ω, 400 Ω, and 600 Ω are connected next to each other (parallel). A current of 1.8 A flows through the first 200Ω resistor. a) What current passes through the second and what current through the third resistor? b) Wh - Lowest voltage
Three resistors with resistors R1 = 10 kΩ, R2 = 20 kΩ, R3 = 30 kΩ are connected in series and an external voltage U = 30 V is connected to them. On which resistor is the lowest voltage? - Aircraft 25161
The average climb angle of the aircraft is 11 ° 20', and its average speed is 400 km/h. How long does it take to climb to a height of 3000m? - 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.
- 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?
Do you have homework that you need help solving? Ask a question, and we will try to solve it.