Question
Granny whizzes around a skating rink and sees her grandson at rest directly in her path. Rather than knock him over Granny picks him up and continues in motion without "braking": Which of these is true according to the Law of Conservation of Momentum? Granny's momentum cannot change Grandson's momentum cannot change All of these are true The total momentum of the two cannot change
Answer
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Vianne
Master · Tutor for 5 years
Answer
D. The total momentum of the two cannot change.
Explanation
## Step 1The Law of Conservation of Momentum states that the total momentum of an isolated system remains constant if no external forces are acting upon it. This principle is a fundamental concept in physics.## Step 2In the given scenario, Granny and her grandson form an isolated system. Granny picks up her grandson while she's still moving, which means an internal transformation of momentum from Granny to the grandson.## Step 3This transformation of momentum means that Granny's and her grandson' individual momentums might change. However, the total momentum of the system (Granny and her grandchildren) should remain constant.## Step 4This is because the total momentum of the system is the sum of the individual momentums of Granny and her grandchildren. Even though individual momentums might change, the sum of these individual momentums (total momentum) is conserved.