PART - 2 CH - 11 Thermodynamics — Physics STD 11 Science — Question

Give the location of the centre of mass of a
(i) sphere, (ii) cylinder, (iii) ring, and (iv) cube, each of uniform mass density. Does the centre of mass of a body necessarily lie inside the body?

The bottom of a ship is made heavy. Why?

A particle starting from rest moves with constant acceleration. If it takes 5.0s to reach the speed 18.0km/h find:

1. The average velocity during this period.
2. The distance travelled by the particle during this period.

Define longitudinal wave motion. What are the essential conditions required for the formation of longitudinal wave motion?

The temperature and the dew point in an open room are 20°C and 10°C. If the room temperature drops to 15°C, what will be the new dew point?

Explain why?
(a) The blood pressure in humans is greater at the feet than at the brain.
(b) Atmospheric pressure at a height of about 6 km decreases to nearly half of its value at the sea level, though the height of the atmosphere is more than 100 km.
(c) Hydrostatic pressure is a scalar quantity even though pressure is force divided by area.

Just as precise measurements are necessary in science, it is equally important to be able to make rough estimates of quantities using rudimentary ideas and common observations. Think of ways by which you can estimate the following (where an estimate is difficult to obtain, try to get an upper bound on the quantity):
The number of strands of hair on your head.