A student wants to find the average speed of a tortoise. She measures how far the tortoise moves every 10 s for 1 minute. Her results are shown in table given below. Time (s) Distance (m) 0 0 10 4 20 8 30 12 40 15 50 20 60 24 Which one of her readings suggests that the tortoise is not moving at a constant speed? How can you tell this from the graph?

The slope of a distance-time graph represents the speed of the object. The straight line in the graph represents the object is moving with uniform speed. Therefore, the graph represents as follows for the given values. The slope OC represents the tortoise is moving with constant speed. Speed of the tortoise decreases during the slope CD and increases from D to E. Again it moves with constant speed from E to F with the same speed of AC. Therefore, From C to E the speed of the tortoise is changing. Hence, from C to E the tortoise is not moving with constant speed.

A student is measuring the time it takes a ball to fall from a height of 2 m to the ground. Her results are shown in table given below. Time (s) 0 . 65 0 . 67 0 . 65 0 . 56 0 . 66 0 . 64 0 . 65 Calculate the mean time it takes for the ball to fall to the ground. Use all seven results.

A mean value represents the average value of all the observations. Mean value = sum of the all values number of the observations Mean value = 0 . 65 + 0 . 67 + 0 . 65 + 0 . 56 + 0 . 66 + 0 . 64 + 0 . 65 7 = 4 . 48 7 = 0 . 64 Therefore, mean time of the ball falling on the ground is 0 . 64 s .

A student is measuring the time it takes a ball to fall from a height of 2 m to the ground. Her results are shown in table given below. Time (s) 0 . 65 0 . 67 0 . 65 0 . 56 0 . 66 0 . 64 0 . 65 Calculate the mean time it takes for the ball to fall to the ground. Use only the results that are not anomalous.

A mean value represents the average value of all the observations. A anomalous value from the given table is 0 . 56 . Hence it should not be considered for calculating the correct mean value. Mean value = sum of the all values number of the observations Mean value = 0 . 65 + 0 . 67 + 0 . 65 + 0 . 66 + 0 . 64 + 0 . 65 6 = 3 . 92 6 = 0 . 65 Therefore, mean time of the ball falling on the ground is 0 . 65 s .

A student is measuring the time it takes a ball to fall from a height of 2 m to the ground. Her results are shown in table given below. Time (s) 0 . 65 0 . 67 0 . 65 0 . 56 0 . 66 0 . 64 0 . 65 Which of the calculations, (with anomalous value) or (without anomalous value), is likely to give the more accurate answer?

A mean value represents the average value of all the observations. A anomalous value from the given table is 0 . 56 . Hence it should not be considered for calculating the correct mean value. Mean value = sum of the all values number of the observations Mean value with anomalous value = 0 . 65 + 0 . 67 + 0 . 65 + 0 . 56 + 0 . 66 + 0 . 64 + 0 . 65 7 = 4 . 48 7 = 0 . 64 Mean value without anomalous value = 0 . 65 + 0 . 67 + 0 . 65 + 0 . 66 + 0 . 64 + 0 . 65 6 = 3 . 92 6 = 0 . 65 Therefore, the more accurate mean time of the ball falling on the ground is 0 . 65 s .

Sketch distancetime graphs for thecar travelling away from its starting point at a constant speed then braking and coming to a stop

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Student's book>Chapter 9 - Measuring Motion>End of chapter review>Q 10

Sketch distance-time graphs for the bike moving at a constant speed then suddenly stopping.

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Student's book>Chapter 9 - Measuring Motion>End of chapter review>Q 11

A student wants to find the average speed of a tortoise. She measures how far the tortoise moves every $10 s$ for $1$ minute. Her results are shown in table given below.

Time (s)	Distance (m)
$0$	$0$
$10$	$4$
$20$	$8$
$30$	$12$
$40$	$15$
$50$	$20$
$60$	$24$

Draw a distance-time graph of these results.

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Student's book>Chapter 9 - Measuring Motion>End of chapter review>Q 11

A student wants to find the average speed of a tortoise. She measures how far the tortoise moves every $10 s$ for $1$ minute. Her results are shown in table given below.

Time (s)	Distance (m)
$0$	$0$
$10$	$4$
$20$	$8$
$30$	$12$
$40$	$15$
$50$	$20$
$60$	$24$

What is the tortoise's average speed over one minute?

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Student's book>Chapter 9 - Measuring Motion>End of chapter review>Q 11

A student wants to find the average speed of a tortoise. She measures how far the tortoise moves every $10 s$ for $1$ minute. Her results are shown in table given below.

Time (s)	Distance (m)
$0$	$0$
$10$	$4$
$20$	$8$
$30$	$12$
$40$	$15$
$50$	$20$
$60$	$24$

Which one of her readings suggests that the tortoise is not moving at a constant speed? How can you tell this from the graph?

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Student's book>Chapter 9 - Measuring Motion>End of chapter review>Q 12

A student is measuring the time it takes a ball to fall from a height of $2 m$ to the ground. Her results are shown in table given below.

Time (s)
$0.65$
$0.67$
$0.65$
$0.56$
$0.66$
$0.64$
$0.65$

Which of these results is anomalous?

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Student's book>Chapter 9 - Measuring Motion>End of chapter review>Q 12

A student is measuring the time it takes a ball to fall from a height of $2 m$ to the ground. Her results are shown in table given below.

Time (s)
$0.65$
$0.67$
$0.65$
$0.56$
$0.66$
$0.64$
$0.65$

Calculate the mean time it takes for the ball to fall to the ground. Use all seven results.

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Student's book>Chapter 9 - Measuring Motion>End of chapter review>Q 12

A student is measuring the time it takes a ball to fall from a height of $2 m$ to the ground. Her results are shown in table given below.

Time (s)
$0.65$
$0.67$
$0.65$
$0.56$
$0.66$
$0.64$
$0.65$

Calculate the mean time it takes for the ball to fall to the ground. Use only the results that are not anomalous.

EASY

Lower Secondary Stage 8

IMPORTANT

Cambridge Lower Secondary Science Stage 8 : Student's book>Chapter 9 - Measuring Motion>End of chapter review>Q 12

A student is measuring the time it takes a ball to fall from a height of $2 m$ to the ground. Her results are shown in table given below.

Time (s)
$0.65$
$0.67$
$0.65$
$0.56$
$0.66$
$0.64$
$0.65$

Which of the calculations, (with anomalous value) or (without anomalous value), is likely to give the more accurate answer?

Sketch distance-time graphs for the car travelling away from its starting point at a constant speed then braking and coming to a stop.

Important Questions on Measuring Motion

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