Themes, topics + expression of a variable from the formula - practice problems
Number of problems found: 330
- The capacitor
The parallel square plates of a 4.5µF Teflon capacitor are 3.2 mm apart. What is the area of the plate? - Working together
Zeru can complete a certain job in 5 days, and Tulu can complete the same job in 3 days. How long will they complete the job if they work together? - The sum 41
The sum of 640.00 was deposited in the first bank for five years, and the interest given was 160.00. Find the rate. - Lightning strike
In a thunderstorm, the formula M=t/5.3 gives the approximate distance, M, in miles, from a lightning strike if it takes t second to hear the thunder after seeing the lightning. If you are 5.4 miles away from the lightning flash, how long will it take the - Transformer 3
A 200/115 V transformer has an LV (Low voltage) side resistance of 0.06 Ohm. What is the resistance referred to HV side (high voltage)? - Together 83245
Jarka and Jana decided to decorate their common room. If Jarka painted it alone, it would take her 4 hours, and Jane 3 hours. How long would they paint the room if they painted together? - Horizontal 83148
The bend has a radius of r = 100 m and is inclined at an angle of 20° to the horizontal plane (= tilt angle). What is the safe (the "best") speed to go through this curve? Sketch the picture regarding NIVS, mark the forces, and calculate. - Braking 83146
A car of mass m=1t moves at a speed v0=54 km/h. What braking force must be exerted to bring the car to a stop in 10 seconds, and how far will the car travel in this time? - Penetrates 83078
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? - Overcoming 83076
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? - Interpretation 83015
A cargo boat with a total weight of 4,500t sailed from the river to the sea. Calculate by how many tons it is possible to increase the weight of the cargo on the boat at sea so that the draft remains the same as in the river. The density of river water is - Simultaneously 82966
The tank with a volume of 15 hl has two inlets. One flows 5 liters per minute, the other 3 liters per minute. How long will it take for the tank to be filled with both inflows simultaneously? - Concerning 82883
Conductor A has an electrical potential of +140V concerning the Earth; conductor B has a potential of -60V. How much electric charge will we transfer from wire B to wire A if we do the work of 4.10-4 Joules? - Dominika 82882
Dominika and Ninka are in the park. A 48 kg girl sits on the right side of the swing at a distance of 1.9 m from the axis of rotation. Dominika acts on the swing on the left side with a specific force at 2 m from the axis. What force should she exert to k - Calculate 82808
Calculate the radius of an iron ball with a density of 7.8g/cm³ and a mass of 7kg. - Determine 82724
A right triangle has an area of 36 cm². A square is placed in it so that two sides of the square are parts of two sides of a triangle, and one vertex of the square is in a third of the longest side. Determine the content of this square. - Resistance 82714
A load of 23.5 ohm is connected to an ideal voltage source of 30V, and a current of 1.2A passes through the circuit. Determine the magnitude of the source's internal resistance and the short-circuit current. - Kilometers 82408
The longest Brazilian river, the Amazon, is ten times longer than the two Czech rivers, Vltava and Berounka. The ratio of the lengths of the Vltava and Berounka is 9:5. At the same time, the length ratio of the Vltava and Morava rivers is 5:4. How many ki - Calculating 82316
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 - Diameter 82212
How many meters of copper wire with a diameter of d=3 mm will be produced from 60 kg of copper scrap if the specific gravity of copper is p=9g/cm³?
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