Themes, topics - practice for 12 year olds - page 3 of 48
Number of problems found: 942
- Companies 82884
The K+S company will mow the meadow in ten hours. The Kosačka company mows the meadow in six hours. How many hours would these companies mow one such meadow if they worked together? - 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 82874
Calculate the moment of force if F = 500 N and the arm's length is 0.8m. Unit N.m - Counterweight 82873
What is the weight of the counterweight of a crane that lifts a 20 t weight? The arm's length is 15 m, and the arm's length with the counterweight is 10 m. Write the answer in tons.
- Supported 82872
An 8-meter-long swing is supported at the center. A 30 kg boy is sitting at one end. How far from the axis of rotation on the other side of the swing must the second boy of mass 40 kg sit? - Grandmother 82869
Grandma wanted to fry steaks for lunch. So she went to buy a large piece of meat. Calculate the knife's contact area with the meat if the grandmother cut with a force of 220 N and exerted a pressure of 1.83 MPa. - Calculate 82808
Calculate the radius of an iron ball with a density of 7.8g/cm³ and a mass of 7kg. - Workers 82802
Five workers do a job in 20 hours. How long will it take two workers to do the same job? - Accumulator 82755
The battery capacity is 50 Ah. With a current of 5A, we charge the accumulator to 100% capacity in 10 hours. To what percentage of capacity can we charge the accumulator with a current of 2A in 15 hours?
- Overtake 82752
I am passing a tractor whose speed is 20 km/h. The length of the tractor with the siding is 10 m. My speed is 50 km/h. How long will I overtake the tractor? - Intervention 82748
The missile flies towards the plane at a 2000 km/h speed. The speed of the plane is 1000 km/h. The intervention is after 1.5 minutes. How far apart were the rocket and the aircraft in the beginning? - Children's 82745
The children's car has wheels with a radius of 15 cm, and its speed is 36 km/h. How many times does the toy car wheel turn in a minute at this speed? - Containers 82736
Two filling machines fill 250 containers in 2 hours. How many containers will 4 machines fill in 3 hours? - Kilometers 82735
Fifteen kilometers in front of us, a car travels at a speed of 70 km/h. We drive at an average speed of 100 km/h. How many minutes will it take us to catch up with the car?
- 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 area of this square. - Railings 82711
Seven part-timers paint 280 m of railings in 5 hours. How many meters of railing will nine part-timers paint in 4 hours? - Soda bottles factory
Two different filling machines fill soda bottles to order. If the first machine worked alone, it would need a third less time to complete the order. How long would it take each machine to complete the job independently if the faster machine worked for 96 - Different 82683
There are candies from 1 to 10 in ten different packages. Each child took two packages. They got so many candies: Anka: 5 Zuzka: 7 Katka: 9 Monica: 15 How many candies does Lucka have? - Quadrilateral 82616
Triangle ABC is divided into line segments. Lines DE and AB are parallel. Triangles CDH, CHI, CIE, and FIH have the same area, namely 8 dm². Find the area of quadrilateral AFHD.
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