You must know the concept of pH of a solution and its relation to the concentration of H+ and OH- ions. pH is a measure of the substance's acidity or basicity. From the definition of Arrhenius, an acid contains an H+ while a base contains a OH- ion. From this definition, we can say that an acidic substance has a higher concentration of H+ ions. Now, I'll introduce here that pH is the value of the negative logarithm of the concentration of H+. In equation,
pH = -log[H+]
The term pOH is therefore also, pOH = -log[OH-]. Therefore, the relationship that connects the two negative logarithms is:
pH + pOH = 14
The pH scale starts from 1 being the most acidic to 14 being the most basic. The neutral pH is 7. Thus, for a pH of 7, the H+ and the OH- concentrations are equal.
pH = 7 = -log[H+][H+] = 1×10⁻⁷ mol/L = [OH-]
Since the concentrations are equal, the ratio is equal to 1.
Answer:
false.
Explanation:
Ok, we define average velocity as the sum of the initial and final velocity divided by two.
Remember that the velocity is a vector, so it has a direction.
Then when she goes from the 1st end to the other, the velocity is positive
When she goes back, the velocity is negative
if both cases the magnitude of the velocity, the speed, is the same, then the average velocity is:
AV = (V + (-V))/2 = 0
While the average speed is the quotient between the total distance traveled (twice the length of the pool) and the time it took to travel it.
So we already can see that the average velocity will not be equal to half of the average speed.
The statement is false
Answer:
t = 5.05 s
Explanation:
This is a kinetic problem.
a) to solve it we must fix a reference system, let's use a fixed system on the floor where the height is 0 m
b) in this system the equations of motion are
y = v₀ t + ½ g t²
where v₀ is the initial velocity that is v₀ = 0 and g is the acceleration of gravity that always points towards the center of the Earth
e) y = 0 + ½ g t²
t = √ (2y / g)
t = √(2 125 / 9.8)
t = 5.05 s
Answer:
129.9 m/s = 130 m/s to 2 s.f
Explanation:
For projectile motion, the initial velocity combined with the angle of launch is used to obtain the initial horizontal and vertical components of the velocity.
u = initial velocity of the projectile = 150 m/s
uₓ = u cos θ = 150 cos 30° = 129.9 m/s
uᵧ = u sin θ = 150 sin 30° = 75.0 m/s
In the motion of a projectile, the motion can literally be separated into vertical and horizontal components.
The vertical component has to do with the acceleration due to gravity (acting downwards) on the projectile and the vertical component of the velocity (which changes all through the motion of the projectile because of the force of gravity manifested in the form of acceleration due to gravity).
But there is no force acting in the horizontal direction, hence, no acceleration in the horizontal direction for projectile motion. This directly translates to a constant velocity in the horizontal direction all through the flight of the projectile.
Hence, the horizontal component of the velocity of the projectile at t = 4 s is the same as the horizontal component of the initial velocity.
Horizontal component of the Velocity at t = 4s is equal to uₓ = u cos θ = 150 cos 30° = 129.9 m/s = 130 m/s
Answer:
3494444444.44444 J
-87077491.39453 J
Explanation:
M = Mass of Earth = 
G = Gravitational constant = 6.67 × 10⁻¹¹ m³/kgs²
R = Radius of Earth = 
h = Altitude = 
m = Mass of satellite = 629 kg
v = Velocity of spacecraft = 
The kinetic energy is given by

The spacecraft's kinetic energy relative to the earth is 3494444444.44444 J
Potential energy is given by

The potential energy of the earth-spacecraft system is -87077491.39453 J