The silver coating on the inner bottle prevents heat transfer by radiation, and the vacuum between its double wall prevents heat moving by convection. The thinness of the glass walls stops heat entering or leaving the flask by conduction.
Explanation:
It is given that,
Initial speed of sprinter, u = 0
Final speed of sprinter, v = 10 m/s
Time taken, t = 1.28 s
a. We need to find the acceleration of sprinter. It can be calculated using first equation of motion as :



b. Final speed of the sprinter, v = 36 km/h
Time, t = 0.000355 h
Acceleration, 

Hence, this is the required solution.
Answer:
option (B)
Explanation:
Intensity of unpolarised light, I = 25 W/m^2
When it passes from first polarisr, the intensity of light becomes

Let the intensity of light as it passes from second polariser is I''.
According to the law of Malus

Where, θ be the angle between the axis first polariser and the second polariser.

I'' = 11.66 W/m^2
I'' = 11.7 W/m^2
Answer:
5.2941176471 kg or 5294.1 grams
Explanation:
g.p.e= mgh
g.p.e/gh=m
180j/10×3.4= m
180/34= m
5.2941 kg= m