Question

A car increase it's velocity from 36km/hr To 72km/hr in 20 sec find the distance travelled by the car during this time

Answer 1

Explanation:

V initial= 36km/hr = 36×5×18= 10 m/s

V final= 72km/hr= 72×5×18= 20 m/s

Time taken = 20 sec

v= u+at

a= v-u/t = 20-10/20

= 0.5 m/s²

for distance travelled S

S= ut+1/2at²

s= 10×20+1/2×0.5×20×20

S= 200+100

S = 300 METRE = 0.3 KILOMETRE

Answer 2

To Find :

• We need to find distance travelled by car.

Solution :

• Initial velocity of car (u) = 36km/hr
• Final velocity of car (v) = 72km/hr
• Time taken = 20 seconds
• Distance travelled = ?

Converting km/hr to m/s

• 1km = 1000 m
• 1hr = 3600sec

36km/hr = 10m/s

72km/hr = = 20m/s

As we know that,

• Acceleration = v - u/t

⇛a = 20 - 10/20

⇛a = 10/20

⇛a = 1/2 m/s²

By using Newton's second law of motion

• s = ut + ½at²

›› s = 10 × 20 + 1/2 × 1/2 × 20²

›› s = 200 + 1/4 × 400

›› s = 200 + 100

›› s = 300m

Hence,

• Total Distance covered by car = 300m

OR in km :-

• 1km = 1000m

›› 300m into km

= 300/1000

• Distance travelled = 0.3Km

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