21. A helicopter is 8.50 m above the ground and climbing at 2.5 m/s. It drops a package from rest (relative to the helicopter). At the moment that the package is released, what is its velocity relative to the ground?

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22. A police car is asked to overtake a red sedan that is 1.6 km ahead of it on the freeway. The red sedan is traveling at 80 km/hr and the police car travels at 100 km/hr. When will the police car overtake the sedan?

21. velocity of package relative to ground = 2.5 m/s

the helicopter is climbing upwards with a velocity of 2.5 m/s with respect to ground. As the package is released. it's velocity will be equal to that of helicopter for the ground observer.

22. time to overtake sedan = 0.08 hr

the velocity of sedan with respect to ground = 80 km/h

the velocity of police car with respect to ground = 100km/h

the velocity of police car with respect to sedan = 100-80 = 20 km/h

therefore

time taken by police car to overtake the sedan = distance/speed = 1.6/20 = 0.08hr