Distance and Displacement |Difference, Problems

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• Post category:Physics

Distance and displacement are two terms which measures the same quantity, length but in different ways. Distance is the total length covered by a moving body while displacement is the possible shortest distance covered by the body. Both quantities are measured in unit of length, meter(m).

Distance

It is the actual length of path covered by body. From speed formula we have,

Speed = Distance / Time

Or, Distance = Speed x Time

Displacement

It is the shortest path covered by the body which can be calculated by differencing initial and final distance value.

Numerically,

Displacement = u – v

Where, u = initial distance & v = final distance.

Also, from velocity formula,

Velocity = Displacement / Time

Or, Displacement = Velocity x Time

Note: Distance is always greater or equals to displacement.

i.e Distance ≥ Displacement

or, Distance / Displacement ≥ 1

Difference Between Distance and Displacement

Difference between distance and displacement.

Numerical Based on Distance and Displacement

Numerical 1

Calculate the value of distance and displacement from following figure.

Distance = 5 + 3 + 5 + 3 = 16m (sum of all distance covered)

Displacement = 3m (shortest possible distance)

Problem 2

On seeing a deer, a lion runs at speed of 40meter/min and catches the deer in 30 minutes. Calculate the distance travelled by lion to catch the prey.

Solution

We have,

Speed = 40m/min

Time = 30min

From distance formula,

Distance = speed x time

= 40m/min x 30min

= 1200 meter

Problem 3

Calculate the distance and displacement covered by a body moving in a circle.

Solution

From the circle,

Distance is equal to the circumference of the circle.

So, Distance = 2πr

And, displacement is zero since the man return to its initial position

Displacement = 0

Hence distance is equal to 2πr and displacement is equal to 0 for the body moving in a circle.

Problem 4

Calculate the distance and displacement covered by body on completing half circle.

Solution

From the semi-circle

Distance is equal to half of the circumference of the circle.

So, Distance= πr

And displacement is equal to the diameter or 2 times the radius of the circle

i.e Displacement = 2r

Hence distance is equal to πr and displacement is equal to 2r for the body moving in semi-circle.