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Multiple choice. Need good explanation. Just started with this topic.1.2

Multiple choice. Need good explanation. Just started with this topic.1.2-example-1

1 Answer

5 votes

Given:

Car P and Q are travelling toward each other.

The speed of P is,


v_p=10\text{ m/s}

Acceleration of car P is,


a_p=2\text{ m/s}^2

The speed of Q is,


v_q=20\text{ m/s}

The cars meet after 5 s.

Acceleration of car Q is,


a_q=1\text{ m/s}^2

To find:

The graph of V-T of the cars

Step-by-step explanation:

The slope of v-T graph shows the acceleration of the object.

AS the cars both have acceleration, the speed vs time graph will be a straight line with positive slopes.

The speed of P in 5 s is,


\begin{gathered} v_p=10+2*5 \\ =20\text{ m/s} \end{gathered}

The speed of Q after 5 s,


\begin{gathered} v_q=20+1*5 \\ =25\text{ m/s} \end{gathered}

The graphs will not intersect each other after 5 s.

Hence, the third one is the correct graph.

User Andrea Girardi
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