Unit conversion - practice for 13 year olds - page 14 of 43
Number of problems found: 843
- Latent heat
How much heat is needed to take from 100 g of water at 20°C to cool to the ice at -18°C? Mass heat capacity c (ice) = 21kJ/kg/°C; c (water) = 4.19 KJ/kg/°C and the mass group heat of solidification of water is l = 334kJ/kg - Therefore 29661
Věra wants to welcome her friend Nada, who will arrive by train at 8:22 a.m. He, therefore, leaves home 1.2 km from the station at 8:00 a.m. and travels at a speed of 3.6 km/h. Will he arrive at the station on time? - Aircraft 4480
Two planes take off simultaneously from airports A and B, fly towards each other, and meet in 20 minutes. The distance between the airports is 220 km, and the average speed of the aircraft flying from airport A is 60 km/h more than the average speed of th - Three examples per-mille
A. Calculate 1.5 ‰ from 4.5 liters of blood. Express the result in milliliters. B. Calculate three ‰ from € 50,000. C. The tray they brought breakfast to the landlord's bed is made of an alloy that contains 830 ‰ of silver. How much silver did they use on - Overload
What overload in g (g-force) would have passed the pilot if he accelerated from 0 to 600 km/h in 3 seconds? - Chained winch
When digging a well, a chained winch balances the material. An empty shackle weighs 8 kg, a total of 64 kg. What force must the worker exert on the crank handle when pulling the shackle with a constant movement from a depth of 5 m if the shaft diameter is - Electricity 6667
A light bulb with power consumption P = 70 W. It is connected to a mains voltage of 230 V. How big is the electric current that flows through it? How much electricity in kWh will it use if it is on for 9 hours 30 minutes? - Four poplars
Four poplars are growing along the way. The distances between them are 35 m, 14 m, and 91 m. At least how many poplars need to be dropped to create the same spacing between the trees? How many meters will it be? - Failure
Drivers of passenger cars have calculated that at a speed of 60 km/h arrives at their destination within 40 minutes. After 20 km, refrain for five minutes due to a technical failure. How fast must it go the rest of the way to the finish come at the schedu - Aircrafts
Above the town, the hall tower flew the plane at a constant speed of 510 km/h, and 15 minutes later, the second plane at a speed of 703 km/h. How long and how far from the town hall will it be for aircraft to catch up? - Heat transfer
We placed a lead object weighing 0.4 kg and 250°C in 0.4 L water. What was the initial temperature of water t2 if the object's temperature and the water after reaching equilibrium was 35°C? We assume that the heat exchange occurred only between the lead o - Aircraft
The aircraft has a fuel tank 68 hl of aviation fuel, and flight consumes 3.6 liters of fuel. Identify the function that expresses the dependence of the fuel volume in the tank on the track distance plane flew by. How many hectoliters of fuel is still in t - Hectoliters 68174
In the meat atlas published by the Jindřich Boll Foundation, it is stated that one kilogram of meat requires 6.5 kg of grain, 36 kg of feed mixture, and 15 cubic meters of water. Laura's slice of beef in the burger weighed 45 grams raw. How many kilograms - Airports 4605
Regular planes fly between the two airports 690 km away. The aircraft takes off from the first airport at 6:30 am at an average speed of 60 km/h faster than the aircraft taking off at 7.00 am from the second airport. The planes always meet at 9.00 am. At - A diesel car
A diesel car costs $2599 more than an unleaded petrol car and travels an average of 25,000km per year. Diesel petrol has a consumption rate of 7.4L per 100km and costs $1.39 per liter. Unleaded gasoline has a consumption rate of 8.5L per 100km and costs $ - Train speed
The troop fired two guns from the same place at 10 minutes and 30 seconds intervals, but a person on a train approaching the place heard a second shot 10 minutes after the first. The speed of the train (in km/hr), supposing that sound travels at 340 m/s, - Deteriorating 78504
The hiker walked for 3 hours at a 4 km/h speed. Due to the deteriorating weather, he increased his pace and walked at 7 km/h for the next hour and a half. At the end of his trip, it started to rain, so he started running at a speed of 20 km/h for 30 minut - Owl A,B,C
Owl a gives a hoot every 7 minutes. Owl b gives a hoot every 9 minutes. Owl c gives a hoot every 5 minutes except when he has heard owl a or b give a hoot within the previous 2.5 minutes. If this happens, owl c doesn't give a hoot. If all three owls give - Grandmother
Mom walked out to visit her grandmother in a neighboring village 5km away and moved at a speed of 4km/h. An hour later, father drove down the same road at an average speed of 64km/h. 1) How long will it take to catch Mom? 2) What is the approximate distan - A truck
A truck left Znojmo at 7 am. He drove to Ostrava at an average of 56 km/h. 15 minutes later. A car went out of Ostrava at the same route from Znojmo at 64 km/h. What time did both vehicles pass and at what distance from Znojmo, if you know that the road d
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