1: a, 2:a, 3:a, 4:c, 5:d, 6:d, 7:c;
It is for safety if you come to a sudden stop like newtons law say if an object is in motion it stays in motion until a force stops it if the bike suddenly stopped then you would fly off because you wold still be going. and the gear helps protect you.
Answer:
(NH4)2Cr2O7
Explanation:
Hope this somehow helped.
Since there's specific heat, you should use Q=mc△T. Depends on if this question also involves phase change or not, you might will need Lf (latent heat of fusion) or Lv (latent heat of vaporisation).