Question

A motorcyclist drives from A to B with a uniform speed of 40 km/h and returns back with a speed of 50 km/h. Find his average speed and average velocity.

Answer 1

Answer:

• average velocity = 0
• average speed = 400/9  km/h

Explanation:

• Motorcyclist drives from A to B with a uniform speed of 40 km/h
• and he returned back with a speed of 50 km/h

we need to find

• average velocity and average speed of Motorcyclist.

So,

Since, He drives from A to B and returns back to the same point A , therefore displacement of motorcyclist will be zero.

and hence is

• the average velocity of motorcyclist = 0

Now,

• Let distance from A to B = x

• time taken for driving from A to B = t₁
• time taken for driving from B to A = t₂

so, total time for driving from A to B and back from B to A = t₁ + t₂

then, Using formula time = distance / speed

→ t₁ + t₂ = ( x / 40 ) + ( x / 50 )

→ t₁ + t₂ = (5 x + 4 x) / 200

→ t₁ + t₂ = 9 x / 200

so, total time taken = 9 x / 200

Now,

Using formula

→ Average speed = total distance covered / total time taken

→ Average speed = ( 2 x ) / ( 9 x / 200 )

→ Average speed = ( 2 x ) ( 200 ) / 9 x

→ Average speed = 400 / 9  km/h

Therefore,

• Average speed of motorcyclist = 400/9  km/h .

Answer 2

Explanation:

______________________

Given :-.

• A motorcyclist drives from A to B. a uniform speed of 40 km/h returns back with a speed of 50 km/h.

______________________

solution :-

supposed dist covered be x speed = dist / time

time 1 = dist / speed = x / 40

time 2 = dist / time = x / 50

average speed = total dist/ total time

= x + x / (x/40 + x /50)

= 2x /(9x /200)

= 2x × 200/9x

= 400x/9x

= 44.44 km /h

hence average velocity = 0 as initial and final position are same

more information :-

• Average velocity:- distance/time interval.
• Average speed:- total distance covered in total time .