A girl drove to a hospital from her home and noted the odometer reading of her car increased by 12 km . the trip took 18 mins . what was her average speed ? If she returned home by the same path 7h30min after she left,what was her average speed and velocity for the entire trip
Answers
i) In first part of the question we have to find the average speed.
Given that, the distance travelled by the girl is 12 km in 18 min.
Time = 18 min = 18/60 = 0.3 hr
Average speed = (Total distance covered)/(Total time taken)
= 12/0.3
= 40 km/hr
Therefore, the average speed is 40 km/hr.
ii) In second part of the question we have to find the average speed and velocity of the entire trip.
She returned home by the same path 7h 30min.
As she returned the home using the same pathway. So, total distance covered by the girl is 24 km (12+12).
Time = 7hr 30 min = 7.5 hr
Average speed = 24/7.5 = 3.2 km/hr
Since, she returned using the same pathways. Also her initial and final points are same i.e. home. So, the total displacement of the girl is 0 km.
Average velocity = (Total displacement)/(Total time)
= 0/7.5 = 0 km/hr