posted by Zach .
An 8 g bullet is shot into a 4.0 kg block, at rest on a frictionless horizontal surface. The bullet remains lodged in the block. The block moves into a spring and compresses it by 7.9 cm. The force constant of the spring is 1400 N/m. What is the impulse of the block (including the bullet), due to the spring, during the entire time interval in which block and spring?