A particle P of mass 0.4 kg is moving under the action of a constant force F newtons - Edexcel - A-Level Maths Mechanics - Question 3 - 2003 - Paper 1

To find the acceleration, we first need to calculate the change in velocity over the change in time.

The initial velocity, ( \mathbf{v}_i = 6 ext{i} - 2 ext{j} ) m/s. The final velocity, ( \mathbf{v}_f = -4 ext{i} + 2 ext{j} ) m/s.

The change in velocity, ( \Delta \mathbf{v} = \mathbf{v}_f - \mathbf{v}_i = (-4 ext{i} + 2 ext{j}) - (6 ext{i} - 2 ext{j}) = -10 ext{i} + 4 ext{j} ) m/s.

The change in time is 4 seconds, therefore the acceleration is given by:

$a = \frac{\Delta \mathbf{v}}{\Delta t} = \frac{-10 ext{i} + 4 ext{j}}{4} = -2.5 ext{i} + 1 ext{j} \text{ m s}^{-2}$