A Block of Mass M = 4

Multiple Choice

A block of mass m = 4.4 kg,moving on frictionless surface with a speed v_i = 9.2m/s, Makes a sudden perfectly elastic collision with a second block of mass Mass shown in the figure.The second block is originally at rest.Just after the collision,the 4.4-kg block recoils with a speed of v_f=2.5m/s. What is the mass M of the second block?

A) 7.7 kg
B) 0 kg
C) 0...kg
D) 0.. kg
E) 0.kg