Answer:
They were produced by stars that lived and died before our solar system was born.
Explanation:
According to what it's understood today, all elements heavier than hydrogen (including helium and excluding some that were created in laboratories) are created through nuclear fusion in the core of stars.
They start fusing hydrogen into helium, then as the star grows older helium is fused into beryllium and so on for all the periodic table.
So as far as science understands it today it's a literal truth that we are made of stars. (as almost everything else)
While skydiving, its not just freely falling under Earth's gravity. Additional force called drag acts against the gravity which slows down the rate of fall. Drag is caused by the air molecules which pushes against the body as it falls through them. This is actually a significant amount of force which slows down the rate of fall of the body. Drag depends on the contact surface area and weight. More the surface area in contact, more would be the drag. The sitting position of the skydiver would experience less drag than the chest down position because of the less contact surface area of the body with the air molecules while in the former case. No two persons have identical body shape and weight. Hence, the rate of fall can be made nearly equal but not exactly equal. This is would be possible when they are having same body position.
Answer:
a) 0.31 rad/s
b) 100 J
c) 6.67 W
Explanation:
(a) the force would generate a torque of:
According to Newton 2nd law, the angular acceleration would be
It starts from rest, then after 15s it would achieve a speed of
(b) The distance angle swept by it is:
Hence the work by the child
c) Average power to work per time unit
Answer:
Explanation:
given,
side slope = 1 : 1
hydraulic depth(y) = 5 ft
bottom width (b)= 8 ft
x = 1
Q = 2,312 ft³/s
n = 0.013
slope of channel = ?
R = 4.69 m
using manning's equation
S = 0.406
