Question

A car, initially at rest, travels 20 m in 4 s along a straight line with constant acceleration. The acceleration of the car is: 1. 0.4 m/s 2 2. 9.8 m/s 2 3. 4.9 m/s 2 4. 1.3 m/s 2 5. 2.5 m/s 2

Answer 1

2.5m/s²

Explanation:

Using the equation of motion S = ut + 1/2at² where;

S is the distance travelled = 20m

u is the initial velocity = 0m/s (car starts from rest)

a is the acceleration = ?

t is the time taken = 4s

To get the acceleration of the car, we will substitute the given parameters into the given equation.

S = ut + 1/2at²

20 = 0(4)+1/2a(4)²

20 = 0+ a/2*16

20 = 8a

divide both sides by 8

20/8 = 8a/8

20/8 = a

a = 20/8

a = 2.5m/s²

Hence the acceleration of the car is 2.5m/s²