if u r talkin bout ppr1 :
Q7) s=100m
u=10m/s
v=20m/s
use V squared = u squared +2as
20*20 = (10*10) + (2*a*100)
u'll get 1.5
and Q)21 :
they gave u th no. of atoms n the mass of each atom, if u multiply them u'll get th mass of the whole substance
n if density of p>q then the same applies 4 the mass
hope i make sense
