Question

A man is stranded in the middle of a perfectly smooth island of ice, where there is no friction between the ground and his feet. Under these circumstances,

• A. he can reach the desired corner by throwing any object in the same direction
• B. he can reach the desired corner by throwing any object in the opposite direction
• C. he has no chance of reaching any corner of the island
• D. he can reach the desired corner by walking on the ground in that direction

Answer 1

Answer: (B)

he can reach the desired corner by throwing any object in the opposite direction

Since the surface is frictionless, there would be no external force and hence no external impulse. Hence, linear momentum would be conserved. So if he throws an object in a particular direction, he would get an impulse in the opposite direction and would acquire a constant velocity.