Answer:
Angle = Ф =
(0) = 0
Hence, it is proved that angle between position vector r and acceleration vector a = 0 and is it never changes.
Step-by-step explanation:
Given vector r(t) = 
As we know that,
velocity vector = v = 
Implies that
velocity vector = 
As acceleration is velocity over time so:
acceleration vector = a = 
Implies that
vector a =

vector a = 
Now scalar product of position vector r and acceleration vector a:
r. a = 
r.a = 
r.a = 0
Now, for angle between position vector r and acceleration vector a is given by:
cosФ =
= 
Ф =
(0) = 0
Hence, it is proved that angle between position vector r and acceleration vector a = 0 and is it never changes.
You will need 1 more equation
Answer:
x = 27.57 in to the nearest hundredth.
Step-by-step explanation:
The longer diagonal is opposite the obtuse angle.
Also as it is a rhombus all sides = 14 in.
Use the Cosine Rule:
x^2 = 14^2 + 14^2 - 2*14^2 cos 160
x^2 = 760.36
x = sqrt 760.36
x = 27.57 in.
Both b and c
I hope it helped u