Unit conversion - practice for 14 year olds - page 7 of 29
Number of problems found: 575
- Bronze, tin and copper
Bronze is an alloy of tin and copper. An alloy of 10% tin and 90% copper is Gunmetal. It is bell metal if it contains 20% tin and 80% copper. How many tons of molten bell metal and copper are needed to make 100 tons of Gunmetal? - Car and motorcyclist
A car and a motorcyclist rode against each other from a distance of 190 km. The car drove 10km/h higher than the motorcyclist and started half an hour later. It met a motorcyclist in an hour and thirty minutes. Determine their speeds. - Fruit juice
Fruit juice contains 37.5% sugar. How much percent of sugar will be in the flavored mineral that we prepare from 100 grams of fruit juice and 1.4 liters of mineral? (1 liter = 1 kg) - Antelope 4440
The cheetah began to chase the antelope, and there was a distance of 120 m between them. Although the antelope ran at 72 km/h, the cheetah caught up with it in 12 seconds. How fast was the cheetah running? - Lead melt
Find the heat needed to melt an object made of lead weighing 250g and an initial temperature of 35°C. Lead melts at 327°C at normal pressure. Mass heat capacity of lead c = 129 J/kg • K and mass latent heat of lead lt (t is the subscript) = 22.6 kJ/kg. - Tunnel
Kubo sits on a train speeding at 108 km/h. At that moment, the train entered the tunnel, which according to Kub's book, was 2 km long. Kubo noticed that the end of the train had left the tunnel 75 seconds later than the locomotive had entered the tunnel. - Thermometer
Immerse a thermometer with a heat capacity of 2.0 J. K-1 in water weighing 67.0 grams. Before water immersion, the thermometer showed a temperature of 17.8 degrees Celsius. After reaching equilibrium, the temperature is 32.4 degrees. What was the water te - Pumps
The first pump flows 16 liters per second into the basin by the second pump 75% of the first and by the third pump half more than the second. How long will it take to fill the basin with all three pumps simultaneously, a volume of 15 m³ (cubic meters)? - Forty-five 81599
Lukas left the Tereza cottage and walked at an average 4 km/h speed. Forty-five minutes later, Jakub followed him on a bicycle from the same cottage. He followed Lukas's route and caught up with him after 20 minutes. What was Jakub's average speed? - Possible 81020
The front of the cycling peloton travels at an average speed of 48 km/h. The cyclist with the green T-shirt lost 5 minutes when he fell. What speed must he drive if he wants to reach the front of the peloton in twenty minutes? Possible? - Calculate 33911
Calculate the volume of 50% KI solution and the volume of 20% KI solution needed to prepare 180g of 30% KI solution. The solution densities are known: ρ50% = 1.54575 g / cm3, ρ20% = 1.16597 g / cm³. - Mushrooms
Grandfather gathered fresh mushrooms. The fifth was wormwood, and we threw it away. The other dried up. He obtained 720 grams of dried mushrooms. How many kilograms did the grandfather collect, and they lost 75% of their weight by drying the mushrooms? - Water inlets
An Inlet valve with a flow rate of 12 liters per second is filled tank for 72 minutes. How long does it take to fill the full tank if we open one more such valve half an hour after? - Performance 66404
A person weighing 50 kg can climb 15 stairs. One step is 18 cm high. Determine a person's performance when: a) slowly climbing the stairs if it took him 13 seconds b) going down the stairs slowly if it took him 10 seconds c) quickly climbing the stairs if - Pedestrian 15741
Cities A and B are 42 km apart. A pedestrian exits city A at a speed of 6 km/h in the opposite direction to city B. 30 minutes later, and a cyclist exits B following the pedestrian at a speed of 24 km/h. How many hours does the cyclist reach the pedestria - Much-expected 9871
The train travels at an average speed of 75 km/h. According to the timetable, he should be at the station in 11 minutes, but he still has 20 km to go. How much-expected delay will appear on the station information board? - Procedure 9191
Behind the tractor, which travels at 12 km/h, they sent a car 3.5 hours later to catch up with him in 45 minutes. What speed does he have to go? Please also explain the procedure. - Connections 4473
The distance between the two airports is 3480 km. There are regular connections from airport 1. The plane takes off at 6:30 am at an average speed of 600 km/h. From airport two at 7:00 am at a speed of 540 km/h. When will they meet? - Average height
In a class are 34 students. The average height of the students is 165 cm. What will be the average height of students in the classroom when two pupils, tall 176 cm and 170 cm, move from this school/class? The average height in meters of all the students i - Cheetah vs antelope
When the cheetah began chasing the antelope, the distance between them was 120 meters. Although the antelope was running at 72km/h, the cheetah caught up with it in 12 seconds. What speed was the cheetah running?
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