There's no reason why the center of gravity must be in a place where
there is a any mass.
The center of gravity is simply a LOCATION ... the place where the
amount of mass in any direction from it is the same amount.
For that matter, whenever you know the location of the center of gravity
for ANY object, you can always go in there and scoop our a tiny spherical
hole at that place. Then the center of gravity won't move, but it will be in an
empty space, 'outside the body' of the object.
Here are a few more points to ponder:
-- The center of gravity of a basketball, beach ball, tennis ball, or any other
inflated ball is the center of the ball, where there is no part of the skin.
-- The center of gravity of a party balloon is somewhere inside the balloon,
where there is no rubber. If the balloon is spherical, then its center of gravity
is the center of the sphere.
-- The center of gravity of a square is the center of the square, not on any
of its sides.
-- The center of gravity of a triangle is the centroid of the triangle, not on any
of its sides.
As Kinetic Energy=half of Mass into Velocity square so as velocity is doubled the K.E of the object is doubled..
Answer:
refractive index of plastic is 1.42
Explanation:
When light ray enters from one medium to other medium then due to transition of light it bends away or towards the normal, this phenomenon is known as refraction of light
So here we know that
here we have
now we have
Answer:
Explanation:
Due to change in the position of 3 kg mass , the moment of inertia of the system changes , due to which angular speed changes . We shall apply conservation of angular momentum , because no external torque is acting .
Initial moment of inertia I₁ = M R² = 3 x 1 ² = 3 kg m²
Final moment of inertia I₂ = M R² = 3 x .3 ² = 0.27 kg m²
Applying law of conservation of angular momentum
I₁ ω₁ = I₂ ω₂
Putting the values ,
3 x .75 = .27 x ω₂
ω₂ = 8.33 rad / s
New angular speed = 8.33 rad /s .
Answer : The change in enthalpy of the reaction is, -310 kJ
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
According to this law, the chemical equation can be treated as ordinary algebraic expression and can be added or subtracted to yield the required equation. That means the enthalpy change of the overall reaction is the sum of the enthalpy changes of the intermediate reactions.
The given main reaction is,
The intermediate balanced chemical reaction will be,
(1) 
(2) 
(3) 
Now we will reverse the reaction 1 and multiply reaction 1 by 2, reaction 2 by 2 and reaction 3 by 3 then adding all the equations, we get :
(1) 
(2) 
(3) 
The expression for enthalpy of formation of 
will be,
Therefore, the change in enthalpy of the reaction is, -310 kJ
