Given :
The mass of the balloon was 1890 kg and had a volume of 11,430 m3 .
The balloon floats at a constant height of 6.25m above the ground.
To Find :
The density of the hot air in the balloon.
Solution :
We know,
Volume × ( Density of surrounding air - Density of hot air ) = mass
Putting given values in above equation, we get :

Therefore, the density of hot air in the balloon is 1.125 kg m³.
Linear expansivity, area expansivity and volume or cubic expansivity are
Kinetic energy is the energy possessed by an object having some mass and moving at some speed due to its motion. Kinetic energy is given as
KE = (0.5) m v²
where KE = kinetic energy
m = mass of the object in motion
v = speed of the object in motion.
it is a scalar quantity and has only magnitude and no direction.
Answer:
5.33 cm
Explanation:
The lens equation states that:

where
f is the focal length
p is the distance of the object from the lens
q is the distance of the image from the lens
In this problem,
p = 8 cm
q = 16 cm ( the sign is positive since the image is real, which means it is formed on the other side of the lens)
Substituting into the equation,

