Chapter 8, Problem 21SP

A ball having a mass of 0.500 kg is thrown at a speed of 20 m/s. Determine the magnitude of its momentum.

To determine

The magnitude of momentum of a ball of mass $0.5\text{ kg}$ thrown at a speed of $20\text{ m/s}$.

Answer to Problem 21SP

Solution: $10\text{}\text{}\text{ kg}\cdot \text{m/s}$

Explanation of Solution

Given data:

$\text{Mass of the ball}=0.5\text{}\text{kg}$

$\text{Speed of the ball}=20\text{ m/s}$

Formula used:

The formula for magnitude of linear momentum of a body is,

$p=mv$

Here, $p$ is the magnitude of the linear momentum of the body, $m$ is the mass of the body, and $v$ is the speed or the magnitude of velocity of the body.

Explanation:

The expression for magnitude of linear momentum of the ball can be written as

$p=mv$

Substitute $0.5\text{}\text{ kg}$ for $m$ and $20\text{ m/s}$ for $v$

$\begin{array}{c}p=\left(0.5\text{}\text{ kg}\right)\left(20\text{m/s}\right)\\ =10\text{}\text{}\text{ kg}\cdot \text{m/s}\end{array}$

The magnitude of linear momentum of the ball is $10\text{}\text{}\text{ kg}\cdot \text{m/s}$.

Conclusion:

Therefore, the magnitude of linear momentum of a ball of mass $0.5\text{ kg}$ thrown at a speed of $20\text{ m/s}$ is $10\text{}\text{}\text{ kg}\cdot \text{m/s}$.