Hi there!
We can calculate linear momentum using the following:
[tex]\large\boxed{p = m v}[/tex]
p = linear momentum (kgm/s)
m = mass (kg)
v = velocity (m/s)
Calculate:
[tex]p = 1000 * 20 = 20000 kg\frac{m}{s}[/tex]
Now, we can relate force, time, and momentum with the following:
[tex]\large\boxed{I = Ft}\\\\[/tex]
I = Impulse (kgm/s)
F = Force (N)
t = time (s)
Rearrange to solve for force:
[tex]F = \frac{I}{t}[/tex]
The impulse is equal to the change in momentum. Since the car comes to a halt, all of its momentum is lost, so:
[tex]I = \Delta p = p_f - p_i = 0 - 20000 = -20000[/tex]
Solve:
[tex]F = \frac{-20000}{0.5} = \boxed{-40000N}[/tex]
**Negative force since the positive direction is towards the wall, and the negative direction is away from the wall.