Advertisements
Advertisements
प्रश्न
A 50 kg man is running at a speed of 18 km h−1. If all the kinetic energy of the man can be used to increase the temperature of water from 20°C to 30°C, how much water can be heated with this energy?
Advertisements
उत्तर
Given:-
Mass of the man, m = 50 kg
Speed of the man, v = 18 km/h = `18xx5/18=5"m/s"`
Kinetic energy of the man is given by
`K=1/2mV^2`
`K=(1/2)50xx5^2`
`K=25xx25=625 J`
Specific heat of the water, s = 4200 J/Kg-K
Let the mass of the water heated be M.
The amount of heat required to raise the temperature of water from 20°C to 30°C is given by
Q = msΔT = M × 4200 × (30 − 20)
Q = 42000 M
According to the question,
Q = K
42000 M = 625
`rArrM=625/42xx10^-3`
`=14.88xx10^-3`
=15 kg
APPEARS IN
संबंधित प्रश्न
The amount of water vapour in air is determined in terms of its ______.
Observe the following graph. Considering the change in volume of water as its temperature is raised from 0°C, discuss the difference in the behaviour of water and other substances. What is this behaviour of water called?
What is the role of the anomalous behaviour of water in preserving aquatic life in regions of cold climate?
Explain the following:
How can you relate the formation of water droplets on the outer surface of a bottle taken out of refrigerator with formation of dew?
On what basis and how will you determine whether air is saturated with vapour or not?
What do you mean by the anomalous expansion of water?
At what temperature is the density of water is maximum? State its value.
Explain the following
A hollow glass sphere which floats with its entire volume submerged in water at 4°C, sinks when water is heated above 4°C.
Explain, why are soft drink bottles not completely filled?
What is the criterion of choosing the two metals for a bimetal strip?
Give reasons for the following:
Even when the water in the lakes is frozen, fish can survive.
In a region with a cold climate the aquatic animals can survive at 4 °C, because _______.
_______ apparatus is used to study the anomalous behaviour of water.
Write scientific reason.
Fish can survive even in frozen ponds in cold regions.
Draw a neat and labelled diagram of Hope’s apparatus.
Observe the following diagram and write the answers to the questions given below.
- Which process does the graph represent?
- What is the range of temperature responsible for the behaviour?
Match the columns:
| Column ‘A’ | Column ‘B’ |
| The density of water is maximum at | (a) 0°C |
| (b) 4°C | |
| (c) 100°C |
