Average acceleration and instantaneous acceleration.

Question: a particle moves according to

x = - t^{2 }+ 2 t
+3,

y = 0.5 t^{2 }- 2.5 t +2.

Find its acceleration at t = 2 s in unit-vector notation and as a magnitude and an angle.

Answer:

**
**

Question: If the position of a particle is given by

with in meters and t in seconds. What must be the units of the coefficients 3, 5 and -2?

Answer:

3 m/s^{4}

5 m/s^{2}

-2 m