Kinetic Energy & Megaton Calculation HELP

[lloyd_lex]

Homework Statement

A) A relatively small impact crater 20 kilometers in diameter could be made by a comet 2 kilometers in diameter traveling at 34.0 (3.40×104 ).

Assume that the comet has a total mass of kilograms. What is its total kinetic energy?

(B) Convert your answer from part A to an equivalent in megatons of TNT, the unit used for nuclear bombs. Comment on the degree of devastation the impact of such a comet could cause if it struck a populated region on Earth. (Hint: One megaton of TNT releases joules of energy.)

Homework Equations

Kinetic energy = 1/2MV^2

The Attempt at a Solution

my attempt:
=1/2*[4.2*10^12]*[3.4*10^4]^2
=2.4276*10^21 joules

For B
i divided my answer from A by 4.2*10^15 since One megaton of TNT releases 4.2*10^15joules of energy

 

[mgb_phys]

The formating seems to have removed some numbers - so we can't check it.
But your method is correct