Answer:
a)

b)

Step-by-step explanation:
Given that
v(t) = 5 t i + t² j - 2 t³ k
We know that acceleration a is given as



Therefore the acceleration function a will be

The acceleration at t = 2 s
a= 5 i + 2 x 2 j - 6 x 2² k m/s²
a=5 i + 4 j -24 k m/s²
The magnitude of the acceleration will be

a= 24.83 m/s²
The direction of the acceleration a is given as

a)

b)
