Question

A car travels with a velocity of 54 kmh-1 for first 20 sec and then with a velocity of 72 kmh-1 for next 30 sec . find avg velocity.​

Answer 1

Answer:

It is 260 km from Patna to Ranchi by air and 320 km by road. An aeroplane takes 30 minutes to go from Patna to Ranchi whereas a deluxe bus takes 8 hours. (a) Find the average speed of the plane. (b) Find the average speed of the bus. (c) Find the average velocity of the plane  (d) Find the average velocity of the bus.

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Answer 2

Answer:

Average Velocity = Total Displacement / Total time taken.

for 1st duration,

54 km/h = 54 × (5/18) m/s = 15 m/s

so, displacement = velocity x time = 15 x 20 = 300 m

for 2nd duration,

72 km/h = 72 × (5/18) m/s = 20 m/s

so, displacement = velocity x time = 20 x 30 = 600 m

Toal displacement = 300m + 600m = 900m

Total time = 20 sec + 30 sec = 50 sec

Hence, Average Velocity = 900/50 m/s = 18m/s = 18 x 18/5 km/h = 324/5 km/h = 64.8 km/h