Question

How much momentum does a $2kg$ object moving at $4\dfrac{m}{s}$ have?

Answer 1

Hint: In order to find the momentum of the given object, we should know first what momentum is. Momentum basically refers to mass in motion. We know that every object has some mass, if they move they give momentum. Simply use the formula of momentum, substitute the given value and get the desired momentum for the question.

Complete step by step solution:
We are given an object of $2kg$ moving with a speed/velocity of $4\dfrac{m}{s}$.
Since, we know that the product of mass and velocity is used to calculate the momentum of any object, which written in formula as:
Momentum$\left( P \right) = mv$, where $m = $mass of object in kilogram and $v = $velocity of the object in metre per second.
Substituting the value of mass and velocity in the momentum formula, we get:
Momentum:
$
  \left( P \right) = mv \\
  P = 2 \times 4 = 8kg\dfrac{m}{s} \\
 $
Since, $1kg = 1000g$ that implies $2kg = 2 \times 1000g = 2000g$. So, our momentum can also be written in grams as:
$
  \left( P \right) = mv \\
  P = 2000 \times 4 = 8000g\dfrac{m}{s} \\
 $
Therefore, a $2kg$ object moving at $4\dfrac{m}{s}$ has momentum , $P = 8kg\dfrac{m}{s}$.

Additional Information:
The variable mass and velocity influence momentum. Any object that is at rest has no momentum, because they have no mass in motion.

Note:
1) We can leave the value in kilogram metre per second until it’s not given to convert into grams.
2) The momentum refers to a vector number. A vector is a quantity whose magnitude and direction both are well defined.
3) If an object having both mass and velocity as large, the momentum it gives will also be large, and vice-versa, as it is directly proportional.