Usha swims in a 90 m pool. She covers 180 m in one minute by swimming from one end to the other and back along a straight path. Find the average speed and average velocity of Usha.
Total distance covered by Usha in 1 min = 180 m.
Displacement of Usha in 1 min = 0 
Give reason for the following observations.
Naphthalene balls disappear with time without leaving any solid.
Give reason for the following observations.
We can get the smell of perfume sitting several metres away.
What is the physical state of water at
a) 25°C
b)00C
c)1000C
What is the physical state of water at
0°C
What is the physical state of water at
100°C
Give two reasons to justify
Water at room temperature is a liquid.
Give two reasons to justify
An iron almirah is a solid at room temperature.
Why is ice at 273K more effective in cooling than water at the same temperature ?
What produces more severe burns, boiling water or steam ?
8. Name A, B, C, D, E and F in the following diagram showing state change :
Mock Test Series
