Horizontal forehead wrinkles are caused by contraction of the frontalis muscles. The frontalis muscles are two large fanlike muscles that extend from the eyebrow region to the top of the forehead. I think this is the answer
Answer
given,
position of particle
x(t)= A t + B t²
A = -3.5 m/s
B = 3.9 m/s²
t = 3 s
a) x(t)= -3.5 t + 3.9 t²
velocity of the particle is equal to the differentiation of position w.r.t. time.

------(1)
velocity of the particle at t = 3 s
v = -3.5 + 7.8 x 3
v = 19.9 m/s
b) velocity of the particle at origin
time at which particle is at origin
x(t)= -3.5 t + 3.9 t²
0 = t (-3.5 + 3.9 t )
t = 0, 
t = 0 , 0.897 s
speed of the particle at t = 0.897 s
from equation (1)
v = -3.9 + 7.8 t
v = -3.9 + 7.8 x 0.897
v = 3.1 m/s
I would say the atmosphere.
Hope this helps!
tectonic plates rubbing against each other.
Answer:
the potential energy of this body is 245 J.
Explanation:
Given;
mass of the body, m = 250 g = 0.25 kg
height from which the body was dropped, h = 100 m
acceleration due to gravity, g = 9.8 m/s²
The potential energy of this body is calculated as;
P.E = mgh
substitute the given values and solve for the potential energy of this body;
P.E = 0.25 x 9.8 x 100
P.E = 245 J.
Therefore, the potential energy of this body is 245 J.