CBSE 11TH PHYSICS - Online Test
for maximum compression
the maximum compression of the spring after the collision = 0.15m
A child running a temperature of 101F is given an antipyrin (i.e. a medicine that lowers fever) which causes an increase in the rate of evaporation of sweat from his body. If the fever is brought down to 98 F in 20 min, what is the average rate of extra evaporation caused, by the drug? Assume the evaporation mechanism to be the only way by which heat is lost. The mass of the child is 30 kg. The specific heat of human body is approximately the same as that of water, and latent heat of evaporation of water at that temperature is about 580 cal
Specific heat of the human body = Specific heat of water = 1000 cal/kg/ °C
The heat lost by the child is
Let m1 be the mass of the water evaporated from the child’s body in 20 min.
Loss of heat through water is
Average rate of extra evaporation caused by the drug = m1 / t
= 86.2 / 200
= 4.3 g/min.
There are three rules on determining how many significant figures are in a number:
- Non-zero digits are always significant.
- Any zeros between two significant digits are significant.
- A final zero or trailing zeros in the decimal portion ONLY are significant.
So keeping these rules in mind, there are 4 significant digit
Initial velocity u = 60 m/s
As it stops so final velocity v = 0 m/s
Time taken t = 2 seconds
We know
v-u = at
Also
From (1), we have
After putting given values, we have
=> s = 120-60 = 60 m
