Mass + time - practice problems
Number of problems found: 83
- Exp decay
An element with a mass of 780 grams decays by 16.3% per minute. How much of the element is remaining after 16 minutes, to the nearest 10th of a gram? - Dorothy
Dorothy feeds her dog during noon time with 2/5 kilograms of dog food and during night time with 3/7 kilograms of dog food. How much is dog food fed to her dog in a week? - 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 - Families 83209
Coal for 15 families lasts 60 days. How many days will the coal last for 20 families? - 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? - Minutes 82607
A) how many kg is 4/5 tons more than 7/10 tons? b) by how many minutes is 1/3 of an hour less than 5/6 of an hour? - Weighing 82602
What is the kinetic energy of a stone weighing 1 kg that falls in free fall 5 seconds from the start of its motion? g= 10m/s squared. - Traveling 82597
What constant braking force is required to stop a car weighing 1 ton in 10 seconds traveling at 50 km/h? - Robinson 82579
Robinson Crusoe came to the island with 4 grains of corn. How many years did it take him to grow enough grain for bread if he got 10 grains from one grain on average and he needed at least 1kg of bole for 1 bread, and 1 grain weighs about 0.2g? (assume on - Harvested 82548
Farmers harvested 1110q of grain from 37 hectares of wheat. a) how many q of wheat did they harvest from 12 hectares? b) how many grains were harvested from 1 m². C) how big is the side of the square of the field from which they harvested 1q of wheat? - 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 - Construction 82214
At the construction site, the sand that belongs to the mortar is sifted through a sieve. At the same time, 1/6 of the coarse sand falls through. Determine how many m³ of sand must be brought in to obtain 2 m³ of sifted sand. - Experimental 82019
3.6 tons of sugarcane were harvested on the experimental plot of 0.2 ha. How many tons of sugarcane can be harvested on a plot of land of 18.6 hectares with the same yield per hectare? - Perpendicularly 81951
A body of mass 4g is shot perpendicularly from the ground and lands in 8s. What is its kinetic energy at the beginning of its trajectory, what speed does it take off, and where does the distance from the ground stop? Thank you - Temperature 81892
By how much °C will the temperature of an iron key weighing 0.004 t change if it receives 360,000 J of heat? ( c of iron is 450 J/kg.°C ) - Surroundings 81843
A copper cylinder weighing 15 kg transferred 114.9 kJ of heat to the surroundings during cooling. By how many degrees Celsius did it cool down? - Traveled 80715
A mass point traveled a distance of 600 m in 2 minutes in uniform motion. How fast was it moving? - Effectiveness 80711
When testing the effectiveness of an electric cooker with data of 220 V, 1200 W, 1 kg of water at a temperature of 15 degrees Celsius was boiled for 8.5 minutes. Calculate the stove efficiency corresponding to these data - Decelerated 80572
A projectile was weighing 20 g shoots at a speed of 800 m. with -1 being dug 100 mm deep into the masonry. How long does it brake in masonry assuming uniformly decelerated motion? - Mechanical 80527
A stone with a mass of 2 kg falls in free fall from a tower with a height of 80 m. What is its kinetic energy, and what is its potential energy: a) At the beginning of the fall, b) In 1 s from the beginning of the fall, c) Upon impact, d) What is its mech
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