MATHS IN SCIENCE
(Biology – cell division)
1. A cell divides every 20 minutes by mitosis (each mother cell gives rise to 2 daughter cells). Starting from a single cell, how many cells will there be after 2 hours?
(Chemistry – concentration of solutions)
2. You have 300 g of a 20% salt solution. How many grams of water do I need to evaporate to obtain a concentration of 60%?
(Physics – speed and time)
3. A helicopter flies at a speed of 72 km/h towards a forest. It emits a sound and hears the echo after 3 seconds. Knowing that the speed of sound in air is 340 m/s, how far from the forest is the helicopter when the sound is emitted?
(Chemistry – gas law)
4. In a closed container, at a temperature of 27°C, the pressure of a gas is 2 atm. If we heat the gas to 127°C, keeping the volume constant, what will be the new pressure? (Temperature is measured in Kelvin.)
(Physics – specific heat)
5. An electrical resistor is used to heat 500 g of water from 20°C to 100°C. Knowing that 1 calorie = 4.18 J, and the specific heat of water is 1 cal/g°C, what electrical energy (in kJ) is required? (Ignore losses.)