Answer: The velocity of the first boat relative to the shore is 1m/sec. The velocity relative to the second boat is 1.5 m/sec.
Explanation:
Each boat receives an impulse Ft equal to 25kg-wt-sec. As a result, the first boat acquires a velocity v3 = Ft/m1 relative to the shore; the second boat acquires a velocity v2 = Ft/m2 also relative to the shore. The velocity of the first boat relative to the second is v = v3 + v2. If we take g to be approximately 10m/sec2, we obtain v1 = 1m/sec; v2 = 0.5m/sec; and v = 1.5m/sec. The problem may also be solved by applying Newton's second law to obtain the acceleration of the boats and then by making use of the formula relating uniform acceleration to velocity.