A 70g rubber ball is thrown with a speed of 10 m/s at a floating 8g balloon. If the balloon is knocked forwards at 40 m/s, how fast is the ball moving after the collision? (Round to the nearest tenths place)

One soccer player (a) is moving at 4 km/h when she kicks the ball while another soccer player (b) is moving at 8 km/h. what statement accurately compares their kinetic energy if they have the same mass? a) both soccer players have the same kinetic energy. b) player b has twice the kinetic energy of player a. c) player b has four times the kinetic energy of player a. d) their kinetic energy can't be compared without knowing their mass.