Laura asks…Speed at which car was traveling?If a car was traveling at 70km/h and a child runs onto 45m ahead, how fast will the vehicle be traveling when the child is hit?
The reaction distance is 29m and braking distance is 28m
Thanks in advance.Nancy answers:70 km / hr = 70000/3600 m/s = 19.44 m/s approx.
At 29 m v = 19.44 m/s
The stopping acceleration is sufficient to reduce v to 0 in 28
Total braking time t, and acceleration a can be determined from
-19.44 = a*t
-28 = 1/2 at^2
solving,
