Answer:
Stellar black holes form when the center of a very massive star collapses in upon itself.
Density = (mass) / (volume)
4,000 kg/m³ = (mass) / (0.09 m³)
Multiply each side
by 0.09 m³ : (4,000 kg/m³) x (0.09 m³) = mass
mass = 360 kg .
Force of gravity = (mass) x (acceleration of gravity)
= (360 kg) x (9.8 m/s²)
= (360 x 9.8) kg-m/s²
= 3,528 newtons .
That's the force of gravity on this block, and it doesn't matter
what else is around it. It could be in a box on the shelf or at
the bottom of a swimming pool . . . it's weight is 3,528 newtons
(about 793.7 pounds).
Now, it won't seem that heavy when it's in the water, because
there's another force acting on it in the upward direction, against
gravity. That's the buoyant force due to the displaced water.
The block is displacing 0.09 m³ of water. Water has 1,000 kg of
mass in a m³, so the block displaces 90 kg of water. The weight
of that water is (90) x (9.8) = 882 newtons (about 198.4 pounds),
and that force tries to hold the block up, against gravity.
So while it's in the water, the block seems to weigh
(3,528 - 882) = 2,646 newtons (about 595.2 pounds) .
But again ... it's not correct to call that the "force of gravity acting
on the block in water". The force of gravity doesn't change, but
there's another force, working against gravity, in the water.
Answer:
C. Chemical energy
Explanation:
The different types of energy listed in this question are:
A) Electrical energy: it is the energy related to the flow of electrical charges (current)
B) Nuclear energy: it is the energy contained in the nuclei of the atoms, and released during nuclear reactions
C) Chemical energy: it is the energy contained in the bonds between molecules, and it is released during chemical reactions
D) Thermal energy: it is the energy associated with the motion of molecules
Photosynthesis is the process that plants use to transform the light energy (coming from the Sun) into chemical energy. In fact, in this process, plants absorb CO2 (from the atmosphere) and solar energy (from the light), and they convert them into sugars (glucose) and oxygen. Therefore, the initial energy coming as solar energy is converted into energy of the bonds of the molecules of glucose (so, chemical energy).
So, the correct option is C).
Answer:
θ=142.9°
Explanation:
d=1 *r
angle ϕ= 37.1°
the line connecting pebble and target should be tangent to a circle so
cos(180-ϕ-θ)=
=
∴ θ=180-ϕ-
θ= 180-37.1-0
θ=142.9°
