Answer

Verified

53.7k+ views

**Hint:**Here, the rate of change of displacement is called velocity. Average speed of a body undergoing linear motion is the ratio of total distance to total time. It is a scalar quantity. Here the speed to move from A to B and time to move from B to A is given. Using the given data, find the average speed of a car.

**Complete step by step answer:**

To describe the apposition of a body, its velocity or acceleration relative to frame of reference we use the kinematic equation. Velocity is the rate of change of displacement.

If the motion starts from rest and the frame of reference should be the same, the initial velocity will be zero. If the motion starts from rest and the frame of reference should be the same. It is a scalar quantity.

The body will move in uniform motion in a straight line, when the body is moving with uniform velocity.

Distance to unit time is called speed. Equation integration results in the distance equation.

Let us consider the distance travelled by the car from A to B to be $x$

The time taken by the car from A to B to be $ = \dfrac{x}{{30}}hour$

The time taken by the car from B to A to be $ = \dfrac{x}{{20}}hour$

Then we can calculate the average speed of the car is given by = $\dfrac{{Total{\text{ }}distance}}{{Total{\text{ time}}}}$

$\Rightarrow s = \dfrac{{x + x}}{{\dfrac{x}{{30}} + \dfrac{x}{{20}}}}$

On further simplification we get

Here $\left( {\left( {\dfrac{x}{{30}} + \dfrac{x}{{20}}} \right) = \left( {\dfrac{{2x + 3x}}{{60}}} \right) = \dfrac{x}{{12}}} \right)$

$\Rightarrow s = 2x \times \dfrac{{12}}{x}$

On multiply the term and we get

$\Rightarrow s = 24km/h$

**Hence option B is the correct option.**

**Note:**The motion starts from rest and the frame of reference should be the same. Then the initial velocity is zero. The velocity equation integration results in the acceleration equation. Displacement may or may not be equal to the path length travelled of an object. Distance to unit time is called speed.

Recently Updated Pages

Why do we see inverted images in a spoon class 10 physics JEE_Main

A farsighted man who has lost his spectacles reads class 10 physics JEE_Main

State whether true or false The outermost layer of class 10 physics JEE_Main

Which is not the correct advantage of parallel combination class 10 physics JEE_Main

State two factors upon which the heat absorbed by a class 10 physics JEE_Main

What will be the halflife of a first order reaction class 12 chemistry JEE_Main

Other Pages

If a wire of resistance R is stretched to double of class 12 physics JEE_Main

Electric field due to uniformly charged sphere class 12 physics JEE_Main

Which of the following distance time graph is representing class 11 physics JEE_Main

The resultant of vec A and vec B is perpendicular to class 11 physics JEE_Main

Choose the correct statements A A dimensionally correct class 11 physics JEE_Main

The figure below shows regular hexagons with charges class 12 physics JEE_Main