A car travels frim Bangalore to mysore on a road that is 150 km long. If half the distance is covered at a speed of 60 km/h and rest at 80 km/h. Find the average speed of the car.
Answers
The work needed to be done is 156187 J.
Given :
Initial velocity(u) = 30 km/h = 30 × 5/18 = 25/3 m/s.
Final velocity(v) = 60 km/h = 60 × 5/18 = 50/3 m/s
Mass = 1500 kg
To Find :
Work needed to be done = ?
Solution :
We know the formula to calculate the work done,
So by using it,
➠ Work done = 1/2mv² - 1/2mu²
➠ W = m/2(v²-u²)
➠ W = 1500/2(50/3²-25/3²)
➠ W = 156187 J
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➤ Additional information :
Work is done when a force that is applied to an object moves that object or body!!
The work is calculated by multiplying the force by the amount of movement of an object itself !!
Formula = f × d
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Answer:
68.57 km/h
Explanation:
time taken in 1st half=75/60= 5/4 hr
time taken in another half=75/80=15/16hr
total time =5/4+15/16=35/16hr
average speed=total distance/total time
=150/35/16=(150*16)/35=30*16/7=480/7=68.57km/ hr