Themes, topics - math word problems - page 16 of 169

Number of problems found: 3370

Vertical movement
Find the length of the vertical path you must travel to lift a weight using a force of 0.01 N and do 1 J of work.
Aluminum - density
The density of aluminium is 2,700 kg/m³. Calculate the mass of an aluminium cube with a volume of 80 cm³.
Aluminum ignote
At what temperature did the temperature stabilise if an aluminium ingot weighing 45 kg, initially at 15 °C, received 4.8 MJ of heat? The specific heat capacity of aluminium is 896 J/(kg·°C).
Paving 2
A construction company needs 8 working days to pave the pavements on two streets if all 6 pavers work. However, only 4 pavers are available because the other two have been reassigned. How many working days will it take the group of 4 pavers to complete th
Didactic test B0
A tourist cycled 28 km on an asphalt road and 25 km on a dirt road, taking 3 hours and 36 minutes in total. At what speeds did the tourist travel each section if he rode 1.4 times faster on the asphalt road than on the dirt road?
Capacity of iron
What was the initial temperature of an iron object weighing 30 kg that absorbed 3.5 kJ of heat when heated to 39 °C? The specific heat capacity of iron is 450 J/(kg·°C).
Calorimetric equation
A 200 g aluminium cylinder at 180 °C was dropped into 3 kg of water at 25 °C. At what temperature did the mixture stabilise? The specific heat capacity of water is 4,200 J/(kg·°C) and of aluminium is 896 J/(kg·°C).
Specific heat
How much heat must be added to convert 25 kg of ice at −15 °C into water at 23 °C? The specific heat of fusion of ice is 333 kJ/kg.
By mass
How much heat must be supplied to completely melt 45 kg of potassium initially at 22.4 °C and bring it to a temperature of 98 °C? The specific heat of fusion is 25.5 kJ/kg, the melting point is 63.32 °C, and the specific heat capacity of potassium is 757.
Elevator efficiency
To what height will an elevator motor with a power of 25 kW and an efficiency of 48.6% transport a cabin weighing 445 kg with seven people (average mass 64 kg per person) in 54 seconds?
Standard
What is the rotational speed in revolutions per minute of a two-pole synchronous motor connected to a standard network with a frequency of 50 Hz?
Crowbar - lever
How much force must be applied to the end of a 2.4 m long crowbar to lift a door weighing 220 kg, if the crowbar rests on the ground and the door stands on it 35 cm from the ground-end?
Height from Impact Velocity
From what height did a body weighing 9.8 kg fall if it hit the surface at a speed of 100 km/h?
Motor efficiency
Calculate the power input of a motor operating at an efficiency of 58% that lifts an elevator car (weighing 390 kg) with twenty boxes (each weighing 25 kg) to a height of 85 m in 29 seconds.
Acceleration - gravity
What is the gravitational acceleration if a body with a mass of 5.8 kg fell from 68 metres and hit the ground at a speed of 60 km/h?
Borrowed
Mr. Douda borrowed 200,000 Sk from the bank at an annual interest rate of 15.4%. He will repay the loan after four years. How many korunas will he have to repay in total?
Emptying a tank
A water tank can be emptied by the first pump in 12 hours, by the second in 9 hours, and by the third in 4 hours. How many hours will it take to empty the tank if all 3 pumps are turned on simultaneously?
Prepare
From two types of tea priced at 1,500 Sk/kg and 2,100 Sk/kg, 29 kg of a mixture priced at 1,650 Sk/kg is to be prepared. How many kilograms of each type of tea should be mixed?
Insulating a house
Five workers are insulating a house at a pace that would allow them to finish the job in 18 days. After three days of work, two workers were called away to another construction site. In how many more days will the remaining workers finish the job?
Kilometers of the journey
A cyclist travelled 199 km over three days. On the first day, he travelled four times as far as on the second day, and on the second day, he travelled 7 km less than on the third day. How many kilometres did he travel each day?

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