# i dont get physics D: helpp

1. Two cars are travelling on a straight stretch of highway at a steady 110 km/h in the same direction. Drivers are advised to maintain a separation of about 3 seconds between cars (more in poor road conditions). How far apart should the two cars be in meters (give you r answer to the nearest meter).
Answers
If you imagine that the car in front is actually not moving, then the car behind takes three seconds to catch up with it. Also you can see that 110km/h is a speed measurement that is given by a distance (kilometres) divided by a time (hours). So this tells us that a distance measurement can be giving by multiplying speed by time. To solve this problem, first you need to convert hours to seconds, and kilometres to metres. 1km = 100m and 1hour = 3600 seconds so 110km/h = [(110 x 1000) metres]/ [3600 seconds] = (110,000/3600) metres per second = 30.5555555... m/s. This tells us that every second the cars are travelling 30.55555... metres, so that in 3 seconds they must travel 91.66666666... metres, which is about 92 metres.
jim360
24 September 2012