Question

200 m in 40
displacement at the end of 2 min
2 Joseph jogs from one end A to the other end
300 m road in 2 minutes 30 seconds and the
and jogs 100 m back to point C in another 1 n
Joseph's average speeds and velocities in jogg
B and (b) from A to C?
ates the a​

Answer 1

Correct Question :

Joseph jogs from one end A to the other end B of a straight road 300 m road in 2 minutes 30 seconds and then turns around and jogs 100 m back to point C in another 1 minute . What are Joseph's average speeds and velocities in jogging :

a) from A to B?

b) from A to C?

Solution :

We will first draw a line diagram to show the movement of Joseph during jogging. Refer to the attachment.

a) Average speed and velocity from A to B

• Total distance from A to B = 300 m

• Total time taken from A to B = 2 minutes 30 seconds

→ 2 × 60 seconds + 30 seconds

→ 120 seconds + 30 seconds

→ 150 seconds

★ Average Speed = Total Distance Covered/ Total time taken

→ Average Speed = $\sf\dfrac{300}{150}$

→ Average Speed = 2 m/s

While travelling from A to B, displacement is also 300 m and the time taken is also 150 s

★ Average Velocity = Displacement/ Total time taken

→ Average Velocity = $\sf\dfrac{300}{150}$

→ Average Velocity = 2 m/s

$\therefore$ When Joseph jogs from A to B, average speed and velocity,both are equal in magnitude each being 2 m/s

b) Average speed and velocity from A to C

• Total distance from A to C = 300 m + 100 m

→ 400 m

• Total time taken from A to B = 2 minutes 30 seconds + 1 minute

→ 2 × 60 seconds + 30 seconds + 60 seconds

→ 120 seconds + 30 seconds + 60 seconds

→ 210 seconds

★ Average Speed = Total Distance Covered/ Total time taken

→ Average Speed = $\sf\dfrac{400}{210}$

→ Average Speed = 1.9 m/s

While travelling from A to C, displacement is (300 - 100) = 200 m and the time taken is also 210 s

★ Average Velocity = Displacement/ Total time taken

→ Average Velocity = $\sf\dfrac{200}{210}$

→ Average Velocity = 0.95 m/s

$\therefore$ When Joseph jogs from A to C, average speed is 1.9 m/s and average velocity is 0.95 m/s