Get expert insights and reliable answers to your questions on IDNLearn.com. Discover comprehensive answers to your questions from our community of knowledgeable experts.

Jack and Jill take 14 minutes to fetch a pail of water by walking 340 m [W], then 129 m [S].Calculate :a. Their total displacementb. Their average speedc. Their average velocity

Sagot :

The displacement refers to a change in the position. We know they walk 340 m to the West and 129 meters to the South. Let's draw the vectors. Also, the displacement is a vector.

To find the total displacement, we have to add the vectors. We'll use i for horizontal components and j for vertical components.

(a) The total displacement is

[tex]\vec{R}=(-340i-129j)m[/tex]

The average speed refers to the quotient between the total distance traveled and the time elapsed.

[tex]\bar{v}=\frac{d_{total}}{t_{total}}=\frac{340m+129m}{14\min }[/tex]

But, transform 14 minutes to seconds. Just multiply 14*60.

[tex]\bar{v}=\frac{469m}{14\cdot60\sec}=\frac{469m}{840\sec }\approx0.56(\frac{m}{s})[/tex]

(b) Their average speed is 0.56 (m/s).

At last, the average velocity refers to the total displacement divided by the time elapsed.

[tex]\begin{gathered} \vec{v}=\frac{\vec{R}}{t}=\frac{(-340i-129j)m}{840\sec }=(-\frac{340i}{840}-\frac{129j}{840})(\frac{m}{s}) \\ \vec{v}=(-0.40i-0.15j)(\frac{m}{s}) \end{gathered}[/tex]

(c) Their average velocity is (-0.40i-0.15j)(m/s)

View image EssamD127990