question on motion calc. (2 Viewers)

[mvrcuriee]

silly question, but when we have questions on 'total distance travelled' w/ displacement/velocity, how do u actually figure it out, i've looked at solutions but i dont actually understand it bc sometimes they add/subtract additional things! i understand how to get other eqns, or rest times but i always get 'distance travelled' parts wrong!
if anyone is able to explain clearly, it would be most appreciated! my exam is on friday :/
an example question in case anyone can explain thru a question;

 

[wollongong warrior]

From the question you've provided
We see that v = 10 - 2t
Meaning, it travels right from the origin until t = 5, where the mass stops and starts travelling back
Since distance doesn't care about direction, you'd sum the distance traveled between t = 0 and t = 5, and then t = 5 and t = 7

 

[mvrcuriee]

From the question you've provided
We see that v = 10 - 2t
Meaning, it travels right from the origin until t = 5, where the mass stops and starts travelling back
Since distance doesn't care about direction, you'd sum the distance traveled between t = 0 and t = 5, and then t = 5 and t = 7

thank you!

 

[wollongong warrior]

If the equation is linear like this
Drawing a v(t) graph and calculating the area underneath the line can be faster since it's js triangles and rectangles
Edit: while taking the initial position as "0" e.g. for your question, x = 5 would become the x axis