Question

The initial position of an object at rest is given by 3i-8j It moves with constant acceleration and reaches
to the position 2i + 4j after 4 s. What is its acceleration?

Answer 1

Since acceleration is constant, so we use the equation for constant acceleration

Vf = Vi + aT   ⁻⁻⁻⁻⁻⁻⁻⁻⁻  (1)

Where Vi is the initial velocity

           Vf the final velocity

           a is acceleration

           T is time taken

Given values are 

Vi = 3i - 8j

Vf = 2i + 4j

T = 4 sec

a = ?

Putting these values in equation (1), we get

(2i + 4j) = (3i - 8j) + a (4)

4 a = (2i + 4j) - (3i - 8j)

4 a = (2i - 3i) + (4j + 8j)

4 a = -i + 12j

a = -1/4 i + 3 j 

This is the required acceleration.

Hope it helps.