Could you assist me with this physics problems? And explanation? Thank you!

w Week 5 work set 1. A 30 cm spring with constant 70 N/m is compressed to 10 cm and placed between two carts. Cart A has mass m = 5kg and mp is unknown. Initially the system is at rest. After it is released it is observed that cart A has three times the velocity of cart B. a) What force must be exerted initially to keep the spring compressed? b) What is the work done to compress the spring? c) By considering conservation of momentum determine the mass mp d) By considering conservation of energy find the velocities of the carts A and B after the spring is released. 2. A 0.30 kg ball is dropped onto a concrete driveway. The ball's velocity before impact is 4.5 m/s and after impact is 4.2 m/s. What is the change in the ball's momentum? 3. A 1.5 kg ball falls onto a floor. Just before it strikes the floor, its velocity is 12 m/s. The ball bounces up with a velocity of 10 m/s. Find the impulse on the ball. 4. A soccer player kicks a soccer ball initially at rest setting it in motion at a velocity of 30 m/s. If the ball has a mass of 0.50 kg and the time of contact is 0.025 s, what is the force exerted on the player's foot