Answer:
Option D
+2
Explanation:
We know that Calcium has 20 electrons and 20 protons. It lost two electrons, it has 20 protons, but only 18 electrons. This makes calcium a positive ion with a charge of +2.
Answer:
a) v = √ 2gL abd b) θ = 45º
Explanation:
a) for this part we use the law of conservation of energy,
Highest starting point
Em₀ = U = mg h
Final point. Lower
Em₂ = ½ m v²
Em₀ = Em₂
m g h = ½ m v²
v = √2g h
v = √ 2gL
b) the definition of power is the relationship between work and time, but work is the product of force by displacement
P = W / t = F. d / t = F. v
If we use Newton's second law, with one axis of the tangential reference system to the trajectory and the other perpendicular, in the direction of the rope, the only force we have to break down is the weight
sin θ = Wt / W
Wt = W sin θ
This force is parallel to the movement and also to the speed, whereby the scalar product is reduced to the ordinary product
P = F v
The equation that describes the pendulum's motion is
θ = θ₀ cos (wt)
Let's replace
P = (W sin θ) θ₀ cos (wt)
P = W θ₀ sint θ cos (wt)
We use the equation of rotational kinematics
θ = wt
P = Wθ₀ sin θ cos θ
Let's use
sin 2θ = 2 sin θ cos θ
P = Wθ₀/2 sin 2θ
This expression is maximum when the sine has a value of one (sin 2θ = 1), which occurs for 90º,
2θ = 90
θ = 45º
That is not true.
<span>According
to the law of conservation of mass, in a chemical reaction, the mass of
the reactants will always be the same as the mass of the products.</span>
Answer:
Explanation:
Given
Velocity of Huck w.r.t to raft 
Perpendicular to the motion of raft
Velocity of Raft in the river 
As Huck is traveling Perpendicular to the raft so he possess two velocities i.e. vertical velocity and horizontal velocity of River when observed from bank
So magnitude of velocity is given by
For direction 
w.r.t river bank
The angle which the Earth's axis with the plane of the orbit.
