Question

A person moving on a motor cycle in a ground takes a turn through 60° on his left after every
50 m. Then find the
magnitude of displacement suffered by him after 9th turn



1) 100 m
2) 50 m

3) 50/3m
4) 20 m

Answer 1

Answer:

I think the answer is 3.

Answer 2

Answer:100

Explanation:

The complete ques is as follows:

A person moving on a motor cycle in a ground  takes a turn through 60° on his left after every  50 m. The magnitude of displacement suffered by him after 9th turn is:

On taking the turn of 60° every 50 m, the motorcyclist will complete a full hexagon after 6 turns and return to point A as shown in figure .

On 7th , 8th and 9th turn he will go from A to G, then from G to H and then from H to I respectively

Initial starting point = A

Final ending point = I

Thus, the displacement = AI = AD

In ΔBCD

DC = BC = 50 m

∠BCD = 120°

∴ ∠CBD = ∠CDB = 30°

∴ ∠ABD = ∠ABC - ∠CBD = 120° - 30° = 90°

Thus ΔABD is a right angled triangle

In ΔBCD, by sine rule

Therefore, in right angled ΔABD  m

Therefore, the magnitude of displacement is 100 m