Question

a man walks 40m North, then 70m East then 40m south. What is his displacement from the starting point?
a)150 m east b)150 m west
c)70 m east d)70 m west e)30 m west​

Answer 1

ANSWER:

• Displacement = 70 m towards east.

GIVEN:

• A man walks 40 m North, then 70 m East and then 40 m south.

TO FIND:

• Displacement of the man from the starting point.

EXPLANATION:

Displacement is the shortest distance between the two points.

Let us say that he starts at the point O and travels in a path ABC.

If we join the initial and final point of the path travelled by him, it will give the displacement of the man.

Distance from O to A = 40 m

Distance from A to B = 70 m

Distance from B to C = 40 m

Distance from O to A = Distance from B to C

We want the displacement which is distance between the points O and C

In rectangle opposite sides are equal. Hence Distance from O to C = Distance from A to B

Displacement = Distance from A to B

Displacement = 70 m towards east.

NOTE : Refer attachment for diagram

ADDITIONAL POINTS:

• Distance is the actual length of the path traversed by a body.

• Distance is scalar whereas displacement is a vector.

• Distance travelled by him = 40 + 70 + 40 = 150 m

Answer 2

GIVEN :-

• A man walks 40 m north.
• And 70 m east
• And 40 m south.

TO FIND :-

• The Displacement.

SOLUTION :-

➵ Note :- For better understanding refer to the attachment first.

Displacement = The shortest distance covered by an object from initial point to final point.

∵ AB = 40m

∵ BC = 70m

∵ CD = 40m

➵ Here we are get a rectangle. so Opposite sides are equal

∵ AB = CD = 40m

∴ BC = AD = 70m

Hence our required placement is AD = 70m east

ADDITIONAL INFORMATION :-

➵ Displacement is a vector quantity .

➵ Displacement can be = 0

➵ Displacement of an object may be positive or negative