A farmer moves along the boundary of a rectangular field ABCD as shown in the figure. He takes 4 minutes to travel across each side. Is the motion of this farmer uniform or non-uniform? Find his average speed over one complete round of the field.

The average speed of a moving object is defined as the total distance covered by it is divided by the total time taken. It is a scalar quantity. In this case, it takes the farmer 4 minutes to travel around each side of the rectangular shape field. The distances travelled on each side will now be calculated as follows: Given distances are- AB = 80 m BC = 40 m CD = 80 m DA = 40 m The farmer's motion is non-uniform since the distances traveled on each side differ. The distances traveled at equal time intervals are not equal in non-uniform motion. Calculate the entire distance traveled and divide it by the total time taken to get the average speed for one complete round of the field. Total distance traveled = AB + BC + CD + DA Total distance traveled = 80 m + 40 m + 80 m + 40 m Total distance traveled = 240 m Total time taken = 4 minutes × 4 sides Total time taken = 16 min Now, we will convert the total time taken into seconds. Total time taken = 16 minutes × 60 seconds / minute Total time taken = 960 seconds Average speed = Total distance traveled Total time taken Average speed = 240 m 960 seconds Average speed = 0 . 25 m s - 1 The farmer's average speed over the full round of the field is therefore approximately 0 . 25 m s - 1 .

E M B I B E

The Living World A book of Science and Technology>Chapter 6 - Motion and Time>Something To Know>Q 3

EASY

7th CBSE

IMPORTANT

Earn 100

Two Cars, A and B, (starting, at the same time, from the same point) are moving with average speeds of $40 km / h$ and $50 km / h,$ respectively, in the same direction. Find how far will Car B be from Car A after $3$ hours.

Important Questions on Motion and Time

EASY

7th CBSE

IMPORTANT

The Living World A book of Science and Technology>Chapter 6 - Motion and Time>Something To Know>Q 4

A car moves with a speed of

40 km / h

for

15

minutes and then with a speed of

60 km / h

for the next

15

minutes. Find the total distance covered by the car in these

30

minutes.

EASY

7th CBSE

IMPORTANT

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Define the term 'Periodic motion. Give two examples of periodic motions that can be used to measure time.

EASY

7th CBSE

IMPORTANT

The Living World A book of Science and Technology>Chapter 6 - Motion and Time>Something To Know>Q 6

Distinguish between uniform and non-uniform motion. Give one example of each.

EASY

7th CBSE

IMPORTANT

The Living World A book of Science and Technology>Chapter 6 - Motion and Time>Something To Know>Q 7

Draw the shape of a distance-time graph for a man, waiting for a bus, standing at one point, on a bus stand.

EASY

7th CBSE

IMPORTANT

The Living World A book of Science and Technology>Chapter 6 - Motion and Time>Something To Know>Q 7

Draw the shape of a distance-time graph for a man, walking on a level, straight and narrow road, at a constant speed.

EASY

7th CBSE

IMPORTANT

The Living World A book of Science and Technology>Chapter 6 - Motion and Time>Something To Know>Q 1

A farmer moves along the boundary of a rectangular field ABCD as shown in the figure. He takes $4$ minutes to travel across each side.
Question Image
Is the motion of this farmer uniform or non-uniform? Find his average speed over one complete round of the field.