Physics for life science
posted by Simeon .
1. A car starts from rest and accelerates at a constant rate to 80km/h in 6s in positive direction. What is the acceleration?
2. After how long will the car speed be 120km/h if it keep accelerating at the same rate as in 1.?
3.After the car reached speed of 120km/h it travels at constant velocity for next 100. What distance does it cover in that 100s?

1. 80 km/h = 22.22 m/s
Divide that by 6s for the acceleration
a = 3.70 m/s^2
2. If the speed reaches 80 km/h in 6 s and the acceleration stays the same, it will reach 120 km/h in 1.5 x 6 = 9 seconds.
3. 120 km/h = 33.33 m/s
Multiply that by 100s for the answer, in meters.
Or, you can multiply 120 km/h by 100/3600 hours, for the distance in km.