A car covers the first half of the distance between two places at a speed of 40 km/h and the second half at 60 km/h. What is the average speed of the car?

Solution

Let, the total distance covered the car be 'd'.
Given,
Speed in the first half = 40 km/hr
Speed in the second half of distance = 60 km/hr

Let the time taken by the car in the first half = t₁Therefore,
Time, $t_{1} = \frac{d / 2}{40} = \frac{d}{80}$

Time taken by car in the second half, t₂ = $\frac{\frac{d}{2}}{60} = \frac{d}{120}$

Now, average speed = $\frac{Total distance travelled}{Total time taken}$

$= \frac{d}{\frac{d}{80} + \frac{d}{120}} = \frac{80 \times 120}{80 + 120} = \frac{9600}{200} = 48 km / hr$

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A car covers the first half of the distance between two places at a speed of 40 km/h and the second half at 60 km/h. What is the average speed of the car?

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Matter In Our Surroundings

A car covers the first half of the distance between two places at a speed of 40 km/h and the second half at 60 km/h. What is the average speed of the car?

Some More Questions From Matter In Our Surroundings Chapter

Convert the following temperatures to Kelvin scale.35°C

Give reason for the following observations.Naphthalene balls disappear with time without leaving any solid.

Give reason for the following observations.We can get the smell of perfume sitting several metres away.

What is the physical state of water ata) 25°C b)00Cc)1000C

What is the physical state of water at0°C

What is the physical state of water at100°C

Give two reasons to justifyWater at room temperature is a liquid.

Give two reasons to justifyAn iron almirah is a solid at room temperature.

Why is ice at 273K more effective in cooling than water at the same temperature ?

What produces more severe burns, boiling water or steam ?

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Convert the following temperatures to Kelvin scale.

35°C

Give reason for the following observations.

Naphthalene balls disappear with time without leaving any solid.

Give reason for the following observations.

We can get the smell of perfume sitting several metres away.

What is the physical state of water at

a) 25°C
b)0⁰C
c)100⁰C

What is the physical state of water at
0°C

What is the physical state of water at
100°C

Give two reasons to justify
Water at room temperature is a liquid.

Give two reasons to justify
An iron almirah is a solid at room temperature.