Question

a car moves along a straight path it covers the first half of the distance at the rate of 40 km per hour and the second half at the rate of 60 km per hour find the average speed and average velocity​

Answer 1

Answer:

i.)avg=(40+60)/2

=100/2

=50

velocity=l×t

=50×5

=250

Answer 2

Answer:

average velocity = average speed = 48 kmph

Explanation:

let, total distance = d

for first half of distance

distance covered = d/2

speed = 40kmph

then, time taken is (distance/speed)

= (d/2)/40 = d/80 ...(1)

for second half of distance

distance covered = d/2

speed = 60kmph

then, time taken is (distance/speed)

= (d/2)/60 = d/120 ...(2)

total time taken

= (1) + (2)

$= d/80 + d/120\\= d( 1/80 + 1/120)\\= d(3/240 + 2/240)\\= d(5/240)\\= d(1/48)\\= d/48$

AVERAGE SPEED

= (total distance covered)/(total time taken)

$= d/(d/48)\\= (d/d)48\\= (1)48$

= 48 kmph

AVERAGE VELOCITY

as the car moves in a straight line part and didn't change it's direction during it's journey

distance = displacement

⇒average velocity = average speed