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A car is moving towards east with a speed of 25km/h. To the driver of the car, a busappears to move towards north with a speed of 25 3 / km h . What is the actual velocity of the bus?1) 050 / ,30 km h east of north 2) 050 / ,30 km h north of east3) 025 / ,30 km h east of north 4) 025 / ,30 km h north of east |
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Answer» the car is moving towards east with a speed of 25 km/h. To the DRIVER of the car, a BUS appears to MOVE towards north with a speed of 25 √ 3 k m / h . What is the actual velocity of the bus? A 50 k m / h , 30 o east of north B 50 k m / h , 30 o north of east C 25 k m / h , 30 o east of north D 25 k m / h , 30 o north of east Solution V b = velocity of bus V c = velocity of car V b c = 25 √ 3 k m / h r now from relative velocity | → V b | = √ ( 25 ) 2 + ( 25 √ 3 ) 2 = 50km/hr for DIRECTION t a n θ = 25 √ 3 25 = √ 3 so ′ θ ′ is from east direction Therefore it will be at 30' east of north Hence (A) is correct |
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