A70 kg high-jumper launches himself in the air with an upward momentum of 315 kg-m/s. what is his initial velocity? a. 4.5 m/s upward b. 9.8 m/s downward c. 70.0 m/s downward d. 385 m/s upward

Freya has a mass of 14kg she is running at 1.1m/s to the left when she runs into eric, who is standing still. eric has a mass of 18kg. after the collision, they continue moving together. what is their velocity after the collision. a. 0.48 m/s to the leftb. 2.5 m/s to the leftc. 0.86 m/s to the leftd. 1.4 m/s to the left