Question

Study the motion of a ball rolling on a straight line as shown here.
(i) Find its displacement and distance covered when it rolls from A to B and then to C. (ii) finally comes back to A.

Answer 1

Answer:

Distance is the total path length traversed or covered by the object. Displacement is the shortest distance between the starting and the end point.

According to the question,

Distance covered by the ball moving from A to C is:

⇒ Length of Path AC = 20 m

Since the shortest distance is also equal to the distance traveled, displacement is also equal to 20 m.

Similarly, Distance when the ball travels from A to B is:

⇒ Path length of AC + Path length of BC

⇒ 20 m + 10 m

⇒ 30 m

Since the displacement is equal to distance traveled, it is also equal to 30 m.

Now when the ball returns to A from B, the distance traveled is:

⇒ Initial Distance + Path length of BC + Path length of AB

⇒ 30 m + 20 m + 10 m

⇒ 60 m

Since the starting point and ending point are same, the displacement is equal to 0 m.

Answer 2

Answer:

Given :-

➭ Study the motion of a ball rolling on a straight line as shown here.

Find Out :-

(i) Find its displacement and distance covered when it rolls from A to B and then to C.

(ii) Finally comes back to A.

Solution :-

⍟︎ Distance covered by the ball when it moves from A to C :

➻ Length of path (AC)

➔ 20 m

Then the shortest distance is equal to the distance traveled.

Henceforth, the displacement is 20 m.

Again,

⍟︎ Distance traveled by the ball when it moves from A to B :

➻ Length of path (AC) + Length of path (BC)

➻ 20 m + 10 m

➔ 30 m

Then, the displacement is equal to distance covered.

Henceforth, the distance covered is 30 m.

Now,

⍟︎ When the ball finally comes back to A then, the distance covered is :

➻ Distance covered + Length of path (BC) + Length of path (AB)

➻ 30 m + 20 m + 10 m

➻ 50 m + 10

➔ 60 m

∴ The ball finally comes back to A then the distance covered is 60 m.