Pi is not involved in the calculation of a triangle's area.
If you're using 'R' to represent 'Radius', a triangle doesn't
have one of those either.
So neither pi nor R is involved in the area of a triangle.
Energy is always needed to preform anything, and chemical energy is one form of energy. Chemical energy is a part of chemical reactions because it involves teh chemicals.
Initial velocity = 0
time = 2.50 s
acceleration = gravity, 9.8 m/s^2
use the equations for linear motion.
s = ut + (1/2)at^2
v = u + at
A. displacement given u, a and t.
s = (0)(2.50) + (1/2)(9.8)(2.50)^2
s = 0 + 4.9(6.25)
s = 30.625 m
three significant figures..
s = 30.6 m
B. final velocity given u, a and t
v = 0 + 9.8(2.50)
v = 24.5 m/s
C. graphs
s vs. t
object starts at zero and displacement increases linearly to (2.5, 30.6) and stops. slope of line is average velocity, s/t
v vs. t
object starts at zero velocity and increases linearly to (2.5, 24.5) and stops. slope of line is acceleration, v/t.
a vs. t
acceleration is gravity, it's constant horizontal line at; y = 9.8. stops at (2.5,9.8)
A hot air balloon rises in the first place because the air inside is hot, which rises. So, if the air inside is not heated, it fails to rise and falls. Warm air rises because the particles get excited and jiggle with the heat, and cause the air to take up more space. So, as the surrounding air is probably colder and denser, the less dense hot air rises up in the hot air balloon.