Answer:
21.35 cm^3
Explanation:
let the volume at the surface of fresh water is V.
The volume at a depth of 100 m is V' = 2 cm^3
temperature remains constant.
density of water, d = 1000 kg/m^3
Pressure at the surface of fresh water is atmospheric pressure,
P = Po = 1.013 x 10^5 N/m^2
The pressure at depth 100 m is P' = Po + hdg
P' = 
P' = 10.813 x 10^5 N/m^2
Use the Boyle's law
P V = P' V'

V = 21.35 cm^3
Thus, the volume of air bubble at the surface of fresh water is 21.35 cm^3.
Answer:
140°
Explanation:
The law of reflection states that the angle of redlection equals to the angle of incidence.
When light rays hit surface at 20°, they also leave the surface at the same angle
Since the whole surface has 180° then subtracting these two angles from total angle gives the the angle between the incident and reflected rays.
180°-20°-20°=140°
The angle of incidence and reflection are equal hence 140/2=70°
The question needed the angle between the incident and reflected rays which is already calculated as 140°
Answer:
The magnitude of the force that each wire exerts on the other will increase by a factor of two.
Explanation:
force on parallel current carrying wire, F = BILsinθ
where;
B is the strength of the magnetic field
L is the length of the wire
I is the magnitude of current on the wire
θ is the angle of inclination of the wire
Assuming B, L and θ is constant, then F ∝ I
F = kI

When the amount of current is doubled in one of the wires, lets say the second wire;

Also, if will double the amount of current on the first wire, then
F₁ = 2F₂
Therefore, the magnitude of the force that each wire exerts on the other will increase by a factor of two.
Hello!
a) Assuming this is asking for the minimum speed for the rock to make the full circle, we must find the minimum speed necessary for the rock to continue moving in a circular path when it's at the top of the circle.
At the top of the circle, we have:
- Force of gravity (downward)
*Although the rock is still connected to the string, if the rock is swinging at the minimum speed required, there will be no tension in the string.
Therefore, only the force of gravity produces the net centripetal force:

We can simplify and rearrange the equation to solve for 'v'.

Plugging in values:

b)
Let's do a summation of forces at the bottom of the swing. We have:
- Force due to gravity (downward, -)
- Tension force (upward, +)
The sum of these forces produces a centripetal force, upward (+).

Rearranging for 'T":

Plugging in the appropriate values:
