Acar of mass 1200 kg traveling westward at 30. m/s is slowed to a stop in a distance of 50. m by the car’s brakes. what was the braking force? select one:
a. 1,800,000 n b. 0.80 n c. 11,000 n d. 2000 n

C. 11000 N

Explanation:

car kinematics :The car moves with uniformly accelerated movement for this movement the following formula apply:

vf²= v₀² + 2* a*d  Formula (1)

vf : final speed (m/s)

v₀ : initial speed (m/s)

a  : acceleration (m/s²)

d  : distance (m)

Car kinetics:  We apply Newton's second law:

∑F= m*a

∑F : Algebraic sum of forces (N)

m : mass (kg)

a  : acceleration (m/s²)

Acceleration Calculation

We replace Vf=0 , v₀= 30 m/s , d=50m  the  formula (1)

0= 30²+ 2*a*50

a= - 30² /2*50 = - 900/100 = -9 m/s²

Braking force Calculation

∑F= m*a

-F =  1200 kg*(-9 m/s²)

F = 10800N

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day