Answer:
Step-by-step explanation:
Volume of asteroid = 4/3 x π x 160³
= 17.15 x 10⁶
mass = volume x density
= 17.15 x 10⁶ x 2600 
= 445.9 x 10⁸ kg 
kinetic energy 
= 1/2 x 445.9 x 10⁸ x( 12.6 )² x 10⁶
= 35.4 x 10¹⁷ J . 
2 )
energy of 15 megaton 
= 4.184 x 10¹⁵ x 15 J
= 62.76 x 10¹⁵ J 
No of bombs required 
= 35.4 x 10¹⁷ / 62.76 x 10¹⁵ 
= 56.4 Bombs .