Question

answer the below questions about speed

Answer 1

1.) Given:

• Distance of shop from home = 2 km
• Total time taken = 1 hour

To find:

• Speed of the boy

Total distance = 2+2 = 4 km (As the boy gies and comes back again)

Speed = distance / time

Speed = 4/1

Spees = 4 km/hr

2.) Given:

• Girl goes one round around circle of radius 5m

To find:

• Distance
• Speed

Distance = 2×pi×r

Distance = 2×3.14×5

Distance = 31.4 metres

As time is not given i am assuming it as 1 minute

Speed = 31.4/60

Speed = 0.5233... m/s

3.)

a) 3m² = 30,000 cm² ( 1 m² = 10,000 cm²)

b) 920 km/min

In km/h = 920×60

= 55,200 km/hr

c) 20×18/5=72 km/h

Answer 2

$\huge\sf\red{Answer-1}$

Given:

⇒ A boy starts form home, goes to shop, which is 2 km away, buys things, and comes in an hour.

Find:

⇒ What is the speed with which he travels.

According to the question:

⇒ We know that the distance is 2 km from his House to shop for 1 single journey and also in the question it is given that he comes back in a hour it means he goes and comes hence the distance he travelled would be twice the distance of his house to the shop $\sf (2 \times 2 = 4).$

Using formula:

★ ${\sf{\underline{\boxed{\green{\sf{Speed = \dfrac{Distance}{Time} }}}}}}$

Calculations:

⇒ $\sf Speed = \dfrac{4}{1}$

⇒ ${\sf{\underline{\boxed{\green{\sf{4 }}}}}}$

Therefore, 4 km/hr is the speed with which he travels.

$\huge\sf\red{Answer-2}$

Given:

⇒ A girl runs along a circular track of radius 5 m starting from point A.

Find:

⇒ What will be the travelled by her and speed.

Using formula:

★ ${\sf{\underline{\boxed{\green{\sf{Distance = 2 \times \pi \times r}}}}}}$

Calculations:

⇒ $\sf Distance = 2 \times 3.14 \times 5$

⇒ ${\sf{\underline{\boxed{\green{\sf{ 31.4 \: m}}}}}}$

Therefore, 31.4 m is the distance she travelled.

Now, the time is not give in the question. So let's take 1 min as the time that's converting the min in seconds.

⇒ $\sf Speed = \dfrac{31.4}{60}$

⇒ ${\sf{\underline{\boxed{\green{\sf{0.5233 \:m/s }}}}}}$

Therefore, 0.5233 m/s is the speed.

$\huge\sf\red{Answer-3}$

⇒ $\sf a) \: 3 \: m^2 = 30000 \: cm^2$

⇒ $\sf b) \: 920 \: km/min = 55200 \: km/hr$

⇒ $\sf c) \: 20 \times \dfrac{18}{5} =72 \: km/hr$