Answer: [tex]-2502N[/tex]
Explanation:
[tex](V_2)^2=(V_1)^2+2ad[/tex]
where;
[tex]V_2[/tex] = final velocity = 0
[tex]V_1[/tex] = initial velocity = 60 km/h = 16.67 m/s
[tex]a[/tex] = acceleration
[tex]d[/tex] = distance
First all of, because acceleration is given in m/s and not km/h, you need to convert 60km/h to m/s. Our conversion factors here are 1km = 1000m and 1h = 3600s
[tex]60km/h(\frac{1000m}{1km} )(\frac{1h}{3600s} )=16.67m/s[/tex]
Solve for a;
[tex](V_2)^2=(V_1)^2+2ad[/tex]
Begin by subtracting [tex](V_1)^2[/tex]
[tex](V_2)^2-(V_1)^2=2ad[/tex]
Divide by 2d
[tex]\frac{(V_2)^2-(V_1)^2}{2d} =a[/tex]
Now plug in your values:
[tex]a=\frac{(0)^2-(16.67 m/s)^2}{2(50m)}[/tex]
[tex]a=\frac{0-277.89m^2/s^2}{100m}[/tex]
[tex]a=-2.78m/s[/tex]
If you're wondering why I calculated acceleration first is because in order to find force, we need 2 things: mass and acceleration.
[tex]F=ma[/tex]
m = mass = 900kg
a = acceleration = -2.78m/s
[tex]F=(900kg)(-2.78m/s)\\F=-2502N[/tex]
It's negative because the force has to be applied in the opposite direction that the car is moving.
