Question

A car is stationary. It accelerates at 0.8 ms^2

for 10 s and then at 0.4 ms^2
for a further 10 s. Use
the equations of motion to deduce the car’s final displacement. You will have to split the journey
into two parts, since the acceleration changes after 10 s.

Answer 1

the car’s final displacement is 60 m

Step-by-step explanation:

Given;

initail velocity of the car, u = 0

acceleration of the car, a = 0.8 m/s²

time of motion, t = 10 s

The first displacement of the car:

`x_1 = ut + (1)/(2) at^2\\\\x_1 = 0 + (1)/(2) (0.8)(10)^2\\\\x_1 = 40 \ m`

The second displacement of the car;

acceleration, a = 0.4 m/s², time of motion, t = 10 s

`x_2 = ut + (1)/(2) at^2\\\\x_2 = 0 + (1)/(2) (0.4)(10)^2\\\\x_2 = 20 \ m`

The final displacement of the car;

x = x₁ + x₂

x = 40 m + 20 m

x = 60 m

Therefore, the car’s final displacement is 60 m