I think its b too but i may be wrong
Answer:
I DONT KNOW WHAT TO DO SORRY
Explanation:
EVEN ME IM NOT SURW
Answer:
43.7 °C
Explanation:
= Coefficient of linear expansion of brass = 
= Coefficient of linear expansion of steel = 
= Initial length of brass = 31 cm
= Initial length of steel = 11 m
= Total change in length = 3 mm
Total change in length would be


The final temperature is 43.7 °C
It's 12.1 m/s, assuming that's the launch velocity that's given.
For projectile motion, velocity's y-component is parabolic/quadratic. It's x-component is constant, so you don't need to know it.