Question

classify the following as element and compound and mixture water oxygen air nitrogen salt sand

Answer 1

oxygen is compound
air is compound
nitrogen is compound
salt is mixture water
sand is elements

Answer 2

Distance travelled in 'n'th second-
S=u+a/2×{2n-1}                              where,  u=0, a=g=10m/s2​​​​​​
​​​distance travelled in fifth second-
S5=0+10/2×{(2x5)-1}
S5=45
distance travelled in second second-
S2=0+10/2×{(2×2)-1}
S2=15
distance travelled in third second-
S3=0+10/2×{(2×3)-1}
S3=25
So,
S2:S3:S5=15:25:45=3: