Answer:
a) The initial speed of the car = 0 m/s
b) The final speed of the car = 160 km/h =44.4 m/s
c) Average speed = 80 km/h = 22.22 m/s
Step-by-step explanation:
a) Since the car starts from rest, the initial speed of the car, u = 0 m/s
It accelerates uniformly to a line 1.0 km away
Therefore, the distance, S = 1.0 km = 1 x 1000 m
Distance, S = 1000 m
It crosses the line at 160 km/h
Final speed, v = 160 km/h
v = 160 x 1000/3600 m/s
b) The final speed, v = 44.4 m/s
c) The average speed is calculated below
Average speed = (Initial speed + Final speed)/2
Average speed = (0+160)/2
Average speed = 160/2 = 80 km/h
Average speed = 80 x 1000/3600
Average speed = 22.22 m/s
Second method
Average speed = Total distance/Total time
Average speed = 1 km/45s = 1000m / 45s
Average speed = 22.22 m/s