# Calculating Force of Car hitting wall

by poole_3
Tags: car, force, wall
 P: 186 To calculate the force it would apply you'll have to know how long the car is impacting the wall for. You can estimate it if you don't have any other information, or calculate it somehow knowing certain properties of the materials of the car if you know that much. I, not having any other information, could estimate the impact to last lets say .2 seconds. Assuming the car impacts the wall to zero speed, the impulse will be equal to the moment it has. p = mv $$\Delta$$p = F$$\Delta$$t and since final momentum is zero, mv = F$$\Delta$$t or, F = $$\stackrel{mv}{/Delta t}$$ 2300 lb's $$\approx$$ 1043 kg (mass of car) 40 mph $$\approx$$ 18 m/s (mps) (velocity of car) We can just estimate $$\Delta$$t to be .2 seconds duration, and you get F to be, F = $$\stackrel{(1043 kg)(18 mps)}{(.2 s)}$$ = 93870 N = 21103 lb's (I converted the weight of the car to the mass of the car in Kg and all other units to SI units, then converted final force back to lb's)