Question

A particle moves for 20 s with speed 6 m/s and
then speed 8 m/s for another 20 s and finally
moves with speed 10 m/s for next 20 s. What is
the average speed of the particle?
​

Answer 1

Answer:

The average speed of the particle will be 8 m/s.

Explanation:

The formula to calculate the average speed is:

ν= Δd/Δt = (Total distance covered) ÷ (Total time taken)

Thus, According to the question,

During the first 20 seconds, the particle moves at a speed of 6 m/s.

∴ the distance (d₁) covered by the particle in the first 20 seconds (t₁) = distance = speed × time = 20 × 6 = 120 m.

During the second phase of 20 seconds, the particle moves at a speed of 8 m/s.

∴ the distance (d₂) covered by the particle in the next 20 seconds (t₂) = distance = speed × time = 20 × 8 = 160 m.

During the last phase of 20 seconds, the particle moves at a speed of 10 m/s.

∴ the distance (d₃) covered by the particle in the last 20 seconds (t₃) = distance = speed × time = 20 × 10 = 200 m.

∴ The average speed of the particle

$= \frac{d_{1} + d_{2} + d_{3}}{t_{1} + t_{2} + t_{3}}$

$= \frac{120 + 160 + 200}{20+20+20}$

$= \frac{480}{60}$

= 8 m/s

Conclusion:

The average speed of the particle will be 8 m/s. [Option-(2) is the correct choice]

#SPJ3

Answer 2

8m/s

Explanation:

we know that Distance=Speed×time

So total Distance:-

20×6=120

20×8=160

20×10=200

120+160+200=480

total time taken:-

20+20+20=60

Now average speed is:-

480/60=8m/s