Aballoon filled with helium gas has an average density of

Average density is defined by following formula

here in order to find out the average density of helium we can fill a balloon of helium gas and then we can find it's volume and its mass.

The ratio of mass and volume of that balloon will help us to find the average density of helium

So by the above experiment the average density of helium is approx 0.179 kg/m^3.

the minimum constant speed at which she can catch the train is 2.7 m/s

given:

acceleration = 0.6

time = 4.5 s

to find:

velocity = ?

formula used:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

solution:

from 1st kinematic equation we get,

v = u + at

u = initial speed of train = 0 m/s

v = final speed of the train

a = acceleration of the train

t = time

v = 0 + (0.6 × 4.5)

v = 2.7 m/s

the minimum constant speed at which she can catch the train is 2.7 m/s