posted by lets go on .
A 2200-kg sport utility vehicle traveling at 96 km/h can be stopped in 0.21 s if it hits a concrete wall. Assume a 60 kg person was in the car that hit this wall. The velocity of the person equals that of the car both before and after the crash, and the velocity changes in 0.21 s.
(a)(a) What is the average force exerted on the person? N
(B)Some people think that they can stop themselves rushing forward by putting their hands on the dashboard. Find the mass of the object that has a weight equal to the force you just calculated.
change in v = 96*10^3/3.6*10^3 = 26.7 m/s
acceleration = change in v/time
26.7/.21 = 127 m/s^2
F = m a = 60*127 = 7619 Newtons
m g = 7619
m = 777 kilograms
(about 1700 pounds weight)