Answer:
a) 456 m
b) 85.6 m/s
Explanation:
The car has an initial velocity of 20 km/h, therefore the initial speed u = 20 km/h. Nothing is said about the initial position and we therefore assume it is equal to 0. Hence the position x is given by the equation
x = (1/2) a t 2 + u t
where a is the acceleration (=8 m/s2) and t is period of time between initial and final positions and u is the initial velocity.
Since the time is given in seconds, we need to convert 20 km/h into m/s as follows:
u = 20 km/h = 20 * 1km/1 hour
1000 m
1 km
1 hour
3600 seconds
= 5.6 m/s
We now have
x = (1/2) (8) 102 + 5.6*10 = 456 m
b) v = at + u = 8*10 + 5.6 = 85.6 m/s
