A 500-G Firework Explodes into Two Pieces of Equal Mass $- 20 \hat { \mathbf { i } } - 20 \hat { \mathbf { j } }$

Multiple Choice

A 500-g firework explodes into two pieces of equal mass at an instant when it is traveling straight up at 10 m/s.If one half shoots off horizontally to the left at 20 m/s,what is the velocity,in m/s,of the other half immediately after the explosion? (The x axis is directed right;the y axis up. )

A) $- 20 \hat { \mathbf { i } } - 20 \hat { \mathbf { j } }$
B) $- 20 \hat { \mathbf { i } } + 20 \hat { \mathbf { j } }$
C) $+ 20 \hat { \mathbf { i } } - 20 \hat { \mathbf { j } }$
D) $+ 20 \hat { \mathbf { i } } + 20 \hat { \mathbf { j } }$
E) $- 20 \hat { \mathbf { i } } + 20 \hat { \mathbf { k } }$