PYQ - Velocity — task. Physics CBSE Live product, Class 9.

Give a long answer to the question given below.

An object in motion changes its position over time. The average velocity describes how fast the position changes in a specific direction and is calculated using displacement divided by time. In contrast, average speed refers to how fast an object moves along its actual path and is found by dividing total distance by total time.

a. A train is \(250\ meters\) long and moves at a constant speed of \(45\ \frac{km}{h}\). How long will it take to cross a bridge that is \(750\ meters\) long?

b. A cyclist rides on a circular track with a radius of \(40\ meters\) and takes \(40\ seconds\) to complete half a circle. What is the average velocity for this half revolution?

a. The equation used to determine the time is

\(Time\ =\ \frac{Velocity}{Distance}\)
\(Time\ =\ \frac{Displacement}{Velocity}\)
\(Time\ =\ Distance \times Velocity\)
\(None\ of\ these\)

The time taken by the train to cross a bridge of length \(750\ m\) is

\(20\ s\)
\(80\ s\)
\(88\ s\)
\(60\ s\)

b. The formula to caluculate the average velocity is

\(Average\ velocity\ =\ {Total displacement} \times {Total time}\)
\(Average\ velocity\ =\ {total distance} \times {Total time}\)
\(Average\ velocity\ =\ \frac{Total displacement}{Total time}\)
\(Average\ velocity\ =\ \frac{Total distance}{Time}\)

The average velocity in half revolution is

\(1\ m/s\)
\(4\ m/s\)
\(2\ m/s\)
\(0.5\ m/s\)

6. PYQ - Velocity

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