Question

A body of mass $m=3.513\text{kg}$ is moving along the $x-$axis with a speed of $5.00{\text{ms}}^{–1}$. The magnitude of its momentum is recorded as
(Consider significant figures)

• A. $17.6{\text{kg ms}}^{-1}$
• B. $17.565{\text{kg ms}}^{-1}$
• C. $17.56{\text{kg ms}}^{-1}$
• D. $17.57{\text{kg ms}}^{-1}$

Answer 1

The correct option is A $17.6{\text{kg ms}}^{-1}$

Given $m=3.513\text{kg}$ and $v=5.00{\text{ms}}^{-1}$
So, momentum $p=mv=17.565$
As the number of significant digits in $m$ is $4$ and in $v$ is $3$, so $p$ must have $3$ (minimum) significant digits.
Hence,
$p=17.6{\text{kg ms}}^{-1}$