A 2.0 kg ball moving at 6.0 m/s perpendicular to a wall rebounds from the wall at 1.0 m/s. What is the magnitude of the impulse exerted on the ball by the wall? O a. 28 N-s O b. 21 N-s O c. 14 N.s O d. 7 N.s Question 9 A 4.0 kg object is released from rest under the influence of gravity alone 140 m above the ground. When it has fallen 100 m its kinetic energy (in J) is (g= 10 m/s) Not yet answered . 3200 O b. 4000 Marked out of 1.50 P Flag question O c. 4800 O d. 2400