A bullet with a mass of 10.0 grams and an initial speed of 800 m/s penetrates a distance 5 cm into a fixed block of wood before stopping. The average magnitude of the force exerted by the block on the bullet was

1) 1.3 x 10⁵ N        

2) 6.4 x 10⁵ N

3) 6.4 x 10⁴ N        

4) 1.3 x10³ N