Answer:
28,400 N
Explanation:
Let's start by calculating the pressure that acts on the upper surface of the hatch. It is given by the sum of the atmospheric pressure and the pressure due to the columb of water, which is given by Stevin's law:

On the lower part of the hatch, there is a pressure equal to

So, the net pressure acting on the hatch is

which acts from above.
The area of the hatch is given by:

So, the force needed to open the hatch from the inside is equal to the pressure multiplied by the area of the hatch:

Answer:
An electric field is a region around a charged object where the object's electric force is exerted on other charged objects. Electric fields get weaker the farther away they are from the charge. An electric field is invisible. You can use the field line to represent it.
Explanation:
Answer:
Terminal speed, v = 6901.07 m/s
Explanation:
It is given that,
Mass of the horizontal bar, m = 30 g = 0.03 kg
Length of the bar, l = 13 cm = 0.13 m
Magnetic field, 
Resistance, R = 1.2 ohms
We need to find the terminal speed oat which the bar falls. When terminal speed is reached,
Force of gravity = magnetic force
..................(1)
i is the current flowing
l is the length of the rod
Due to the motion in rods, an emf is induced in the coil which is given by :
, v is the speed of the bar


Equation (1) becomes,



v = 6901.07 m/s
So, the terminal speed at which the bar falls is 6901.07 m/s. Hence, this is the required solution.
Answer:
intensity of sound at level of microphone is 0.00139 W / m 2
sound intensity level at position of micro phone is 91.456 dB
EXPLANATION:
Given data:
power of sound P = 31 W
distance betwen microphone & speaker is 42 m
a) intensity of sound at microphone is calculated as


= 0.00139 W / m 2
b) sound intensity level at position of micro phone is

where I_o id reference sound intensity and taken as

= 91.456 dB
Answer:
The minimun height is 242 [m]
Explanation:
We can solve this problem by using the principle of energy conservation, where potential energy becomes kinetic energy. We will take the point where the Falcon reaches the speed of 69 (m/s), as the point where the potential energy is zero, i.e. it will be the reference point.
At the reference point all potential energy has been transformed into kinetic energy, therefore the kinetic energy can be calculated.
![E_{k}=0.5*m*v^{2} \\ where:\\v = velocity = 69 [m/s]\\m = mass = 480[g] = 0.480[kg]\\E_{k} = kinetic energy [J]\\E_{k} =0.5*0.48*(69)^{2} \\E_{k} =1142.64[J]](https://tex.z-dn.net/?f=E_%7Bk%7D%3D0.5%2Am%2Av%5E%7B2%7D%20%5C%5C%20where%3A%5C%5Cv%20%3D%20velocity%20%3D%2069%20%5Bm%2Fs%5D%5C%5Cm%20%3D%20mass%20%3D%20480%5Bg%5D%20%3D%200.480%5Bkg%5D%5C%5CE_%7Bk%7D%20%3D%20kinetic%20energy%20%5BJ%5D%5C%5CE_%7Bk%7D%20%3D0.5%2A0.48%2A%2869%29%5E%7B2%7D%20%5C%5CE_%7Bk%7D%20%3D1142.64%5BJ%5D)
Now we can calculate the elevation with respect to the reference point using the definition of the potential energy.
![E_{p}=m*g*h\\ E_{p}=E_{k} \\therefore\\h= E_{p}/(m*g)\\h= 1142.64/(.48*9.81)\\h=242[m]](https://tex.z-dn.net/?f=E_%7Bp%7D%3Dm%2Ag%2Ah%5C%5C%20E_%7Bp%7D%3DE_%7Bk%7D%20%5C%5Ctherefore%5C%5Ch%3D%20E_%7Bp%7D%2F%28m%2Ag%29%5C%5Ch%3D%201142.64%2F%28.48%2A9.81%29%5C%5Ch%3D242%5Bm%5D)