Answer:
The ancient Greeks counted the Earth's Moon and Sun as planets along with Mercury, Venus, Mars, Jupiter, and Saturn. Earth was not considered a planet, but rather was thought to be the central object around which all the other celestial objects orbited. ...... Jupiter is composed of gases — hydrogen and helium, mostly — all ... the largest planet in the solar system, the gas giant just doesn't have ... But unlike the sun, it lacks the necessary amount to begin fusion, the process that fuels a star. ... to 80 times more massive than it is at present to be considered a star.
Answer:
Matter is radioactive and decays over time.
Explanation:
Becquerel and the Curies discovered the radioactivity.
The Curies died because they did a lot of experiments using Radio and other elements.
The other alternatives are concepts that are known for a long time.
Answer:
speed: 35m/s
direction: left
Explanation:
Assuming the right side is the positive direction:
before explosion:
P = mv = 0
after explosion:
P' = 15P + 5P
(Set the velocity of the 15kg piece after explosion as v1' and the velocity of the 5kg piece after explosion as v2')
P' = 0.75mv1' + 0.25mv2'
P' = (15kg)v' + (5kg)(105m/s)
P' = 525kg/m/s + (15kg)v1'
P = P'
525kg/m/s + (15kg)v1' = 0
(15kg)v1' = -525kg/m/s
v1' = -35m/s
<u>speed = |-35| = 35m/s</u>
<u>direction is to the left since the right side is the positive direction.</u>
<span>Matter consisting of one atom type is called an element.</span>
Answer:
C) 464 N
Explanation:
The equation of the forces acting on the skydiver is:
where
(mg) is the weight of the skydiver, acting downward, with
m being the mass of the skydiver
g is the acceleration of gravity
R is the air resistance, acting upward
a is the acceleration of the skydiver
In this problem:
m = 80 kg
g = 9.8 m/s^2
a = 4.0 m/s^2
Solving the equation for R, we find the force of air resistance:
