A car moves in a circle of radius 20 m in 50 s with a uniform speed. Find the speed.

Given, Radius r = 20 m , Time t = 50 s Distance covered by car is the perimeter i.e., s = 2 πr Speed, v = s t = 2 π r t ⇒ v = 2 × 3 . 14 × 20 50 ⇒ v = 2 . 5 m / s The speed at which car moves is 2 . 5 m / s .

Express 36 km h - 1 in m s - 1 .

Given, Speed = 36 km h - 1 Converting 1 km h - 1 in m s - 1 . 1 km h - 1 = 1 × 1000 3600 = 5 18 m s - 1 Therefore, 36 km h - 1 = 36 × 5 18 = 10 m s - 1

Average speed Average velocity ≥ 1 . Interpret.

We know that, Distance > | Displacement | - - ( 1 ) , where | | gives the magnitude of a vector. Since Average speed = Distance time and Average velocity = Displacement time , from equation ( 1 ) , we can derive that, Average Speed ≥ Average velocity Or Average Speed Average velocity ≥ 1 Therefore, the average speed is greater than or equal to the magnitude of average velocity.

Express 15 m s - 1 in km h - 1 .

Given, Speed = 15 m s - 1 Converting 1 m s - 1 in km h - 1 . 1 m s - 1 = 1 × 1 1000 1 3600 = 18 5 km h - 1 Therefore, 15 m s - 1 = 15 × 18 5 = 54 km h - 1

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Explain the difference between uniform velocity and variable velocity.

Important Questions on Motion

HARD

Science>Physics>Motion>Measuring the Rate of Motion

A bus is travelling the first one-third distance at a speed of

10 km h^{- 1}

, the next one-fourth at

20 km h^{- 1}

and the remaining at

40 km h^{- 1}

. What is the average speed of the bus?

MEDIUM

Science>Physics>Motion>Measuring the Rate of Motion

A car moves in a circle of radius

20 m

50 s

with a uniform speed. Find the speed.

EASY

Science>Physics>Motion>Measuring the Rate of Motion

Express

36 km h^{- 1}

m s^{- 1}

MEDIUM

Science>Physics>Motion>Measuring the Rate of Motion

A bridge is

400 m

long. A

150 m

long train crosses the bridge at a speed of

50 m s^{- 1}

. Time taken by the train to cross it is _____.

MEDIUM

Science>Physics>Motion>Measuring the Rate of Motion

Abdul, while driving to school, computes the average speed for his trip to be

20 k m / h .

On his return trip along the same route, there is less traffic, and the average speed is

30 k m / h .

What the average speed for Abdul’s trip is?

MEDIUM

Science>Physics>Motion>Measuring the Rate of Motion

\frac{Average speed}{|Average velocity|} \geq 1

. Interpret.

MEDIUM

Science>Physics>Motion>Measuring the Rate of Motion

Joseph jogs from one end A to the other end B of a straight

300 m

road in

2 m i n

30 s

and then turns around and jogs

100 m

back to point C in another

1 m i n

. What are Joseph’s average speeds and velocities in jogging from A to C?

EASY

Science>Physics>Motion>Measuring the Rate of Motion

The distance between two stations is

240 km

. A train takes

4

hours to cover this distance. Calculate the speed of the train.

MEDIUM

Science>Physics>Motion>Measuring the Rate of Motion

An artificial satellite is moving in a circular orbit of radius

42250 k m .

Calculate its speed if it takes

24 h o u r s

to revolve around the earth?

MEDIUM

Science>Physics>Motion>Measuring the Rate of Motion

A car travels with a speed

12 {ms}^{- 1}

, while a scooter travels with a speed

36 km h^{- 1}

. Which of the two travels faster?

EASY

Science>Physics>Motion>Measuring the Rate of Motion

Under what condition(s) is the magnitude of the average velocity of an object equal to its average speed?

MEDIUM

Science>Physics>Motion>Measuring the Rate of Motion

Joseph jogs from one end A to the other end B of a straight

300 m

road in

2 m i n

30 s

and then turns around and jogs

100 m

back to point C in another

1 m i n

. What are Joseph’s average speeds and velocities in jogging from A to B?

EASY

Science>Physics>Motion>Measuring the Rate of Motion

Express

15 m s^{- 1}

km h^{- 1}

MEDIUM

Science>Physics>Motion>Measuring the Rate of Motion

A boy begins to walk eastward along a street in front of his house and the graph of his position from house is shown in the following figure. His average speed for whole time interval is equal to :
Question Image

MEDIUM

Science>Physics>Motion>Measuring the Rate of Motion

Suppose the two photographs, shown in Fig.1 and Fig. 2, had been taken at an interval of $10 seconds$ . If a distance of $100 m$ is shown by $1 cm$ in these photographs, calculate the speed of the blue car.

Question Image