Question

Each of two cars is moving at a constant speed. The ist car's velocity is 15 m/s: the 2nd car's velocity is 20 m/s. A) On the same graph, plot the velocity vs time for each car for 10 seconds. B) On a second graph, plot the displacement vs. time for each car. Assume that they started from the same point. C) After 6 seconds how far apart are the cars?

Answer 1

Given data:

Speed of car 1;

`u_1=15\text{ m/s}`

Speed of car 2;

`u_2=20\text{ m/s}`

Part (A)

Velocity time graph:

Part (B)

Displacement-time graph:

Part (C)

The displacement is given as,

`s=u* t`

The displacement of car 1 after t=6 s is given as,

`\begin{gathered} s_1=u_1*(6\text{ s}) \\ =(15\text{ m/s})*(6\text{ s}) \\ =90\text{ m} \end{gathered}`

The displacement of car 2 after t=6 s is given as,

`\begin{gathered} s_2=u_2*(6\text{ s}) \\ =(20\text{ m/s})*(6\text{ s}) \\ =120\text{ m} \end{gathered}`

Therefore, the separation between the cars after 6 s is given as,

`\begin{gathered} \Delta s=s_2-s_1 \\ =(120\text{ m})-(90\text{ m}) \\ =30\text{ m} \end{gathered}`

Therefore, after 6 seconds the separation between the cars is 30 m.