Question

An object moves with a speed of 20 m/s for 3 seconds and then moves with a speed of 30 m/s for 2 seconds. The average speed of the object is *


20 m/s

24 m/s

15 m/s

10 m/s​

Answer 1

Answer:

24 m/s

Explanation:

As per the provided information in the given question, we have :

• An object moves with a speed of 20 m/s for 3 seconds.
• Then, it moves with a speed of 30 m/s for 2 seconds.

We are asked to find the average speed of the object.

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Average speed is defined as total distance divided by total time to cover certain distance. As formula, we can write it as :

$\bigstar \underline{ \boxed{ \sf{ Speed_{(avg)} = \dfrac{Total \: Distance}{Total \: Time} }}}$

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Finding total distance :

⇒ Total distance = Distance covered in first time + Distance covered in second time

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† Distance covered in first time :

• Speed = 20m/s
• Time = 3 seconds

⇒ Distance = Speed × Time

⇒ Distance = 20 m/s × 3 s

⇒ Distance = 60 m

† Distance covered in second time :

• Speed = 30 m/s
• Time = 2 seconds

⇒ Distance = Speed × Time

⇒ Distance = 30 m/s × 2 s

⇒ Distance = 60 m

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⇒ Total distance = 60 m + 60 m

⇒ Total distance = 120 m

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Calculating total time :

⇒ Total time = 2s + 3s

⇒ Total time = 5 s

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Substituting the value of total time and total distance in the formula of average speed.

⇒ Average speed = $\sf \dfrac{120 \: m}{5 \: s}$

⇒ $\underline{\boxed{\sf {Average \: speed = 24 \: m/s}}} \: \: \bigstar$

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Therefore, average speed of the object is 24 m/s.