1 state the laws of refraction and define refractive index

2 A beam of light is incident from air to water at an angle of 30°. Find the angle of refraction if the refractive index of water is 4/3​

Explanation:

Momentum of an object is defined as the product of the mass of object and the velocity with which it is moving.

p = mv

where, p = momentum, m= mass and v= velocity

mass m = 0.7 Kg and v = 20 m/s

p = 0.7×20 = 14 Kg-m/sec

Therefore, momentum of the object  = 14 kg-m

Answer:

1) 15.6

2) 2.03

Explanation:

The power output of the electric toaster, P = 2,400 W

The voltage rating of the power outlet, V = 120 V

The number of hours the toaster is used during a month = 6.5 hours

1) Electrical energy, E = Electrical power, P × Time, t

The electrical energy dissipated by the toaster, 'E', is given as follows;

E = 2,400 W × 6.5 hrs = 15,600 Wh = 15.6 kWh

The electrical energy dissipated by the toaster, during the measured month in kWh, E = 15.6

2) Let 'C' represent the monthly cost of toaster and let 'B' represent the amount charged by the local power company, we have;

The charges for (electrical) power by the local power company, B = $0.13/kWh

The monthly cost of the toaster, C = E × B

∴ C = 15.6 kWh × $0.13/kWh = $2.028

By rounding off to 2 decimals, the monthly cost of the toaster (in $), C ≈ 2.03.

Answer:

In coastal areas, strong winds and powerful waves break off soft or grainy rocks from hardier rocks. Too much weathering occurs, it might break off parts of the cliff and be dangerous to humans, or animals.

Rain has acid in it which could eat up the cliff.

Explanation:

Answer:

K.E = 400

Explanation:

Given the following data;

Mass = 0.02kg

Velocity = 200m/s

To find the kinetic energy;

Kinetic energy can be defined as an energy possessed by an object or body due to its motion.

Mathematically, kinetic energy is given by the formula;

[tex] K.E = \frac{1}{2}MV^{2}[/tex]

Where;

K.E represents kinetic energy measured in Joules.

M represents mass measured in kilograms.

V represents velocity measured in metres per seconds square.

Substituting into the formula, we have;

[tex] K.E = \frac{1}{2}*0.02*200^{2}[/tex]

[tex] K.E = \frac{1}{2}*0.02*40000 [/tex]

[tex] K.E = 0.02*20000 [/tex]

K.E = 400

Answer:

If I was the white mouse, I would either find somewhere to hide that matches my fur color to camoflouge with or dig into the dirt so less visible.

To find white colour habitat.

If I was the white mouse, I would find white colour place for living because in that white colour the predators can't see me and i will be safe from them so we can conclude that finding white colour habitat is the best choice to safe myself.

Learn more about survive here: https://brainly.com/question/24323334

Answer:

hydraulic lift pump moves the lift piston out in a series of movements. and a hydraulic brake moves it out in one short break.

Answer:

Sunlight allows plants to perform photosynthesis, a process which is required for plant growth and health. ... Plants that are denied sufficient light will eventually lose their color and die. Plants deprived of light will grow upward, stretching their stems more rapidly that usual, searching for light.

Answer:

Sunlight allows plants to perform photosynthesis, a process which is required for plant growth and health. ... Plants that are denied sufficient light will eventually lose their color and die. Plants deprived of light will grow upward, stretching their stems more rapidly that usual, searching for light

Explanation:

i got this from  

https://sciencing.com/what-happens-to-plants-if-they-have-no-sun-12486997.html#:~:text=Sunlight%20allows%20plants%20to%20perform,for%20plant%20growth%20and%20health.&text=Plants%20that%20are%20denied%20sufficient,that%20usual%2C%20searching%20for%20light.

Answer:

That is because we apply less Work.

Brainliest?? I hope this helps!!!

Explanation:

Answer:

check the point where the output device's field wiring is connected to the output rack. ( C )

Explanation:

Given that an indicator light on the output module is indicating that a signal has been sent to the output point where the failed single output device is connected , the best line of action to properly indicate the output device that has filed in the PLC system, is to check the point where the output device's field wiring is connected to the output rack in the PLC system.

A PLC system is a computer control system ( especially Industrial ) that helps in the monitoring the states of input and output devices in an industry.

Answer:

I can't see option dear

Explanation:

Answer: James headache will subside first

Explanation: powder medicines usually get absorbed faster therefore having a quicker effect

Answer:

Nuclear power plants are fueled by uranium, which emits radioactive substances. Most of these substances are trapped in uranium fuel pellets or in sealed metal fuel rods. However, small amounts of these radioactive substances (mostly gases) become mixed with the water that is used to cool the reactor.

Answer:

             air       water      iron        helium

v(m/s)   280     2200      17780     39682

Explanation:

The speed of a wave depends on the physical properties of the medium where it travels, in the case of a longitudinal wave such as sound, it depends on the resistance to deformation (volume modulus and the density of the medium

         v = [tex]\sqrt{ \frac{B}{ \rho } }[/tex]

in the mentioned materials they are constant  

             air       water      iron        helium

B           1 10⁵    2.2 10⁹    140 10⁹   0.05 10⁹

ρ           1.28     997        7874       1.26

v(m/s)   280     2200      17780     39682

Explanation:

A 4kg mass is under the action of a resultant force of (a) 4 N (b) 8N and (c) 12 N What are the resulting accelerations?

Given that,

Mass, m = 4 kg

(a) Force = 4 N

We know that,

Force, F = ma

Where

a is accelertaion,

a= F/m

a = 4/4 = 1 m/s²

(b) F = 8 N

a= F/m

a = 8/4 = 2 m/s²

(c) F = 12 N

a = 12/4 = 3 m/s²

Hence, this is the required solution.

Answer:

W = 30 N

Explanation:

Applying the summation of torques about the wedge for equilibrium, taking the clockwise direction as negative. Since the ruler is balanced horizontally about the wedge. Therefore, the summation of all torques acting about the wedge must be equal to zero.

[tex](70\ N)(40\ cm - 10\ cm)-(30\ N)(50\ cm-40\ cm)-(W)(100\ cm - 40\ cm) = 0\\W(60\ cm) = (70\ N)(30\ cm)-(30\ N)(10\ cm)\\\\W = \frac{1800\ N.cm}{60\ cm}[/tex]

W = 30 N

Answer:

FALSE

Explanation:

You breath in oxygen and your blood takes it through your body then you breath it out as carbon dioxide

Answer:

[tex]L=11.3\ kg-m^2/s[/tex]

Explanation:

Given that,

Angular speed of a skater, [tex]\omega=3\ rot/s=18.84\ rad/s[/tex]

The moment of inertia of the skater, I = 0.6 kg-m²

We need to find the angular momentum of the skater. The formula for the angular momentum of the skater is given by :

[tex]L=I\omega[/tex]

Substitute all the values,

[tex]L=0.6\times 18.84\\\\L=11.3\ kg-m^2/s[/tex]

So, its angular momentum is equal to [tex]11.3\ kg-m^2/s[/tex].

Answer:

10.1 m/s

Explanation:

Let the coordinates of the pelican's position be (x, y).

Now, since it is dropped from a height of 12.3 m, then initial velocity is zero and using Newton's 2nd law of motion, we have;

12.3 = 0 - ½gt²

½gt² = 12.3

t² = 12.3 × 2/9.8

t² = 2.51

t = √2.51

t = 1.5843 s

Now, it travels 16.0m horizontally before it hits the water below. Using the formula, distance = speed × time, we have;

16 = v_x•t

Thus;

16 = v_x × 1.5843

v_x = 16/1.5843

v_x = 10.1 m/s

Now, the velocity in the vertical y-direction is zero.

Thus;

v = √((v_x)² + (v_y)²)

v = √((10.1² + 0²))

v = 10.1 m/s

Answer:

Explanation:

Use the one-dimensional equation for displacement:

Δx = v₀t + [tex]\frac{1}{2}at^2[/tex] where Δx is the displacement, v₀ is the initial velocity (which is 0 since someone had to be holding the penny still before it was dropped), t is the time it takes to travel a certain distance (which is given as 4 seconds), and a is the acceleration due to gravity which is -9.8 m/s/s. Filling in:

Δx = [tex](0\frac{m}{s})(4s)+\frac{1}{2}(-9.8\frac{m}{s^2})(4s)^2[/tex] I'm going to expand this first so you can see how the units work out. First of all, anything times 0 is 0, so what is right in front of the plus sign goes to 0 and I'm going to leave it out. How this looks expanded without doing any of the actual math yet is:

Δx = [tex]\frac{1}{2}(-9.8\frac{m}{s^2})(4^2s^2)[/tex] which makes it apparent that the seconds-squared cancel each other out, leaving us with the meters only. NOW doing the math and rounding to 2 sigfig's even though there's only 1 in the number 4:

Δx = 78 m(the negative would only be used if the question we were answering was how far the penny had to fall, which would then use the negative sign to indicate that the penny is falling to a point that is below th point from which it was released. Since height is a distance measurement, it will never be negative. Keep in mind, asking how far the penny fell is not the same thing in physics as asking how tall the building was that the penny fell from.)

Answer: Hello Results of examples 5.4 and 5.5 are missing from your question but I was able to find it online and use it to resolve your question

answer :

a) 1780 m^3/sec

b)  23.81 m

Explanation:

a) calculate the number of m^3 of water flowing through an OTEC plant charge

assumption : assuming an ideal heat engine

 Q / t   =  m*c*∆T * (eff) / t

1e^9 J/s = 1g/cc *V(1cal/g°C) * 2°C (6.7%)*(4.184J/cal) / t

Hence:  V / t ( number of m^3 of water ) = 1.78e^9 cc / sec = 1.78 * 10

= 1780 m^3/sec

b) Determine the diameter of pipes

Given that the water flows at  4m/s  ( velocity )

1780 m^3 /sec = A * V  ------ ( 1 )

A = π*d^2/4 =  1780 / 4 = 445 m^2  -------- ( 2 )

v = 4 m/s

Back to equation 2

d^2 = ( 445 * 4 ) / π

      ≈ 567

∴ necessary diameter ( d ) = [tex]\sqrt{567}[/tex] = 23.81 m

Answer:

=> Rheostat is an electric device used as a variable resistance, like the regulator of the fan. It is used to change the electric resistance in the electric circuit.

=> Rheostat works on the principle of Ohm’s law. Ohm’s law states that current in a circuit is inversely proportional to the resistance at the given temperature.

[tex] \infty \infty \infty [/tex]

Answer:

C

Explanation:

Since gravitational force is inversely proportional to the square of the separation distance between the two interacting objects, more separation distance will result in weaker gravitational forces

I hope this helps a little bit

The correct Option is :

=》(C) The square of the distance that separates them

where,

f = gravitational force

r = distance between the objects

Answer:

(a) h = 1.5 m (b) v = 5.29 m/s

Explanation:

1. Given that,

Mass of a rollercoaster cart, m = 4500 kg

It has 67,500 J of gravitational potential  energy.

We know that, the gravitational potential  energy is given by :

[tex]E=mgh[/tex]

Put all the values,

[tex]h=\dfrac{E}{mg}\\\\h=\dfrac{67500}{4500\times 10}\\\\h=1.5\ m[/tex]

2. The kinetic energy of an object is given by :

[tex]E=\dfrac{1}{2}mv^2\\\\v=\sqrt{\dfrac{2E}{m}}\\\\v=\sqrt{\dfrac{2\times 63000}{4500}}\\\\v=5.29\ m/s[/tex]

Hence, this is the required solution.

Answer:

1/2 m u^2     initial Kinetic Energy of body

m g h        Potential Energy body attains as it rises to height

1/2 m u^2 = m g h      conversion of KE to PE

h = u^2 / ( 2  g)

Answer:

none. 0. for work to be done the object has to have displacement, and even though you were exerting force, the box did not move and s work is o it could also be 50 but I'm sure it is 0

Explanation: