How many atoms of Aluminum are contained in this compound?

This means that the mass of one mole of aluminium atoms will be 26.982 g . As you know, one mole of any element contains exactly 6.022⋅1023 atoms of that element. This means that if you know how many moles of aluminium you have in 4.55 g , you can use Avogadro's number to find the number of atoms.

Explanation:

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