Question
Question: Which has greater momentum, an elephant at rest or an ant in motion? (A) Elephant (B) Ant (C) ...
Which has greater momentum, an elephant at rest or an ant in motion?
(A) Elephant
(B) Ant
(C) Neither has momentum
(D) Same
Solution
Hint
We will use momentum = velocity x mass (p=m.v) . We will thus consider linear momentum of both the objects given to us in the question and find the required solution. It is true that the elephant has significant mass but for it to have momentum, it needs velocity.
Complete step by step answer
The mass of an elephant is clearly more than an ant but as an ant is moving with a certain velocity. Therefore, it possesses a linear momentum whereas the elephant is at rest so the linear momentum of the elephant comes out to be zero.
p=m.v This is the case for the ant where m is the mass of the ant and v is its velocity.
In the case of the elephant p=m.v⇒p=m.0=0.
Therefore, the correct options are (B). The momentum of an ant is clearly larger.
Additional Information
The law of momentum coms under Newton’s second law.
Which states that the force acting on a body is equal to the rate of change of its momentum.
i.e. dtdp=F
Note
Noticing large bodies such as that of an elephant one tends to think that every aspect possessed by it is larger as compared to its smaller counterpart in the question, but we have to take into account all the values of the vector and scalar quantities before solving.