Question

A motorcyclist moving from point A to point B with an

average speed of 40km/h. The motorcyclist took a U-turn from B and came

back to where he started with an average speed of 60 km/h. Vihaan pondered

upon this situation and found out that the distance travelled and displacement

are different.

a) Why was the distance travelled and displacement different?

b) Can displacement be greater than distance? Give reason.

c) Calculate the average speed for the entire journey of the motorcyclist.​

Answer 1

Answer:

An object has moved through a distance. Can it have zero displacement? If yes, support your answer with an example.

Answer: An object can have zero displacement even when it has moved a distance and shown some displacement. This takes place when the final position of an object coincides with its own initial position. Let's say, if a person moves around circular area and comes back to the place from where he started then the displacement will be zero.

2. A farmer moves along the boundary of a square field of side 10 m in 40 s. What will be the magnitude of displacement of the farmer at the end of 2 minutes 20 seconds from his initial position?

Answer:

Here, Side of the given square field = 10m

so, perimeter of a square = 4*side = 10 m * 4 = 40 m

Farmer takes 40 s to move along the boundary.

Displacement after 2 minutes 20 s = 2 * 60 s + 20 s = 140 seconds

since in 40 s farmer moves 40 m

Therefore, in 1s the distance covered by farmer = 40 / 40 m = 1m

Therefore, in 140s distance covered by farmer = 1 � 140 m = 140 m. Now, number of rotation to cover 140 along the boundary= Total Distance / Perimeter

= 140 m / 40 m = 3.5 round

Thus, after 3.5 round farmer will at point C of the field.

Thus, after 2 min 20 seconds the displacement of farmer will be equal to 14.14 m north east from initial position.

3. Which of the following is true for displacement?

(a) It cannot be zero.

(b) Its magnitude is greater than the distance travelled by the object.

Answer: None of the above statements is actually true for displacement.

First statement is completely false because displacement can be zero in case of a circular path. Second statement is also false because displacement is less than or equal to the distance travelled by the object in case of motion in opposite direction.

Hope this was helpful

Explanation: