Examples for secondary school students - page 21 of 229
Number of problems found: 4578
- Transformation of voltage
A current of 0.5 A flows through the transformer's primary coil connected to a voltage of 120 V. Calculate the voltage and current in the secondary coil if the transformation ratio is equal to the number 5. - Bulb lifespan
The probability that the bulb will burn for more than 800 hours is 0.2. There are 3 light bulbs in the hallway. What is the probability that after 800 hours, at least one will be lit? - Granulate 83503
Bathing water should have a pH value in the range of 6.8 - 7.2. How much granulate should we add to increase the pH value from 6.2 to 7 if a dose of 100g/10m³ increases the pH by approx. 0.1? P.S. It's not 800 grams. - Conductive 83502
A conductive soap bubble with a radius of r=2 cm and charged to a potential of φ= 10000 V will burst into a drop of water with a radius of r1= 0.05 cm. What is the potential φ1 of the drop? - Acceleration 83493
A body with a mass of 5 kg moves in a vertical downward direction with an acceleration of a= 12 m/s². What force acts on it in addition to its weight? - Temperature 83492
How much heat is needed to turn 1kg of ice at a temperature of -10℃ into steam at a temperature of 100℃? - Calculate
A bicycle rotates with a frequency of f= 25 Hz. By braking, its rotation can be slowed down evenly and the bicycle stops after a time of t0= 30 s from the start of braking. Calculate the angular acceleration Ԑ and the number of revolutions the bicycle mak
- Coordinates of line points
I have a point A=[2,1] and a line y+x-5=0. How do I determine the coordinates of point A', which is the image of point A according to the given straight line? - Numbers 6D
Find out how many natural six-digit numbers exist whose digit sum is four. - Lifetime - bell curve
Laser lifetime follows a normal distribution with a mean of 7000 hours and a standard deviation of 600 hours. What is the probability that the laser will fail before 6000 hours? What is the probability that the laser will last at least 7500 hours? - Distance
If Danka increases her walking speed by 1km/h, she will cover a distance greater than 20 km in 4 hours. If she decreases her speed by 1km/h, she will not cover more than 20 km in 5 hours. At what speed did Danka walk? (s=v. t;s- distance, v- speed, t- tim - Circumscribed circle ABC
Triangle ABC, with sides a = 15 cm, b = 17.4 cm, and c = 21.6 cm, is circumscribed by a circle. Calculate the area of the segments determined by the sides of the triangle. - Circumscribed triangle
Calculate the radius of the circle of the circumscribed triangle, which has side dimensions of 8, 10, and 14 cm. - Playmakers + coach
In a basketball game, two pivots, two wings, and one point guard play. The coach has three pivots, four wing players, and two playmakers available on the bench. How many different five players can a coach send to the board during a game? - Components 83328 Divide the number 112 into three components, x, y, and z, so that x: y = 7: 5 and y: z = 3: 4 apply.
- Refrigerator, lemonades
How many possible ways can we store three lemonades, four mineral waters, and two juices in the refrigerator next to each other? - Married pairs
In how many ways can we seat five guests at a table, two of whom are married and want to sit next to each other? - Probability 83308
There are 10 parts in the box, and 3 of them are defective. Let's choose 4 components at random. What is the probability that it will be among them a) 0 defective, b) just one defective component, c) just two defective components, d) exactly 4 defective c - Acceleration 83305
A body of mass 500 kg is lifted with a uniformly accelerated rectilinear motion using a rope. Determine the acceleration at which the rope breaks if it sustains a load of 15,000 N. - Acceleration 83304 The acceleration of a mass point during its rectilinear movement decreases uniformly from the initial value a0 = 10 m/s2 at time t0 = 0 to a zero value for a period of 20 s. What is the speed of the mass point at time t1 = 20 s, and what is the path of th
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