i just got hit on the head by a basketball.
story of my life.

The Pelican  must aim differently than where the fish appears to be because light is refracted from air to water.

Refraction is the change in the direction of a wave at the interface between two media. The effects of refraction are easily seen when light is travelling from air to water hence objects are not really where they appear to be when viewed above the water surface.

Hence, the Pelican  must aim differently than where the fish appears to be because light is refracted from air to water.

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Answer:

I guess the Ans for second one is gravitational force

Answer:

Solar Impulse is a Swiss long-range experimental solar-powered aircraft project and Conventional Aircraft are the atmosphere-only aircraft that have been around since the Wright Flyer's first takeoff. Though modern craft are much more advanced and capable than that early model, Conventional Aircraft have been superseded in modern times by the AeroSpace Fighter, which can operate in both atmosphere and space.

Explanation:

Answer:

velocity = 16.05 m/s

Explanation:

inelastic collision formula:

m1u1 + m2u2 = (m1 + m2)v

m1 = 4kg

u1 = 20m/s

m2 = 15kg

u2 = 15m/s

find v ?

m1u1 + m2u2 = (m1 + m2)v

(4×20) + (15×15) = (4+15)v

80 + 225 = 19v

305 = 19v

19v = 305

v = 305/19

v = 16.05 m/s

Answer:

Power_input = 85.71 [W]

Explanation:

To be able to solve this problem we must first find the work done. Work is defined as the product of force by distance.

[tex]W = F*d[/tex]

where:

W = work [J] (units of Joules)

F = force [N] (units of Newton)

d = distance [m]

We need to bear in mind that the force can be calculated by multiplying the mass by the gravity acceleration.

Now replacing:

[tex]W = (80*10)*3\\W = 2400 [J][/tex]

Power is defined as the work done over a certain time. In this way by means of the following formula, we can calculate the required power.

[tex]P=\frac{W}{t}[/tex]

where:

P = power [W] (units of watts)

W = work [J]

t = time = 40 [s]

[tex]P = 2400/40\\P = 60 [W][/tex]

The calculated power is the required power. Now as we have the efficiency of the machine, we can calculate the power that is introduced, to be able to do that work.

[tex]Effic=0.7\\Effic=P_{required}/P_{introduced}\\P_{introduced}=60/0.7\\P_{introduced}=85.71[W][/tex]

Answer:

Police officer

Explanation:

Because police officers wants to gather information on what happens and question people to know everything. That is what Derick is doing

Answer:Yes

Explanation:yeah i think it could be possible because the universe is so far and wide its probably infinite and if we did i personally believe that we would be absolutely be annihilated by them because we would be so far behind technology wise we would have no use for the\

Answer:

a) ll and Ill only

Explanation:

Let the mass of the wrench = m

and the mass of the astronaut = M

Initially, the velocity of the astronaut and wrench are zero.

The astronaut throws the wrench in one direction and subsequently recoils back with a velocity in the opposite direction.

Let v and V be the velocity of the wrench and the velocity of the astronaut respectively.

In space, there is no external force acting, the momentum must be conserved.

So, m(0)+M(0)=m(v)+M(V)

So, 0=mv+MV

[tex]\Rightarrow mv=-MV[/tex] ...(i)

Here, the momentum of the wrench = mv, and the momentum of the astronaut= MV. The negative sign showing that both the momentum are in opposite direction.

Therefore, the momentum of the wrench is equal and opposite to the momentum of the astronaut.

According to Newton's second law, the rate of change of momentum = applied force.

Let it take [tex]\Delta t[/tex] seconds to change the momentum.

So, for the wrench

[tex]m(v-0)/\Delta t= F_w \\\\\Rightarrow m(v-0)=F_w\Delta t \\\\\Rightarrow mv=F_w\Delta t \cdots(ii)[/tex]

Here, [tex]F_w\Delta t[/tex] is the impulse applied to the wrench.

Similarly, for the astronaut

[tex]M(-V-0)/\Delta t= F_a[/tex] [negative sign (-V) for opposite direction]

[tex]\Rightarrow M(-V-0)=F_a\Delta t \\\\\Rightarrow -MV=F_a\Delta t[/tex]

Here, [tex]F_a\Delta t[/tex] is the impulse applied to the astronaut.

So, the impulse on the astronaut.

By using equations (i) and (ii)

[tex]F_a\Delta t=F_w\Delta t[/tex]

Therefore, the impulse applied to the wrench is equal and opposite to the impulse applied to the astronaut.

Hence, option (a) is correct.

Answer:

3.333 m/s^2

Explanation:

50/15 = 3.33 m/s^2

Answer: Kinetic Energy to Electrical.

Explanation: The magnet is rotated as a result of the spinning wheels, and this results in a powerful stream of electrons, therefore converting kinetic to electrical.

Answer:

A I think

Explanation:

because what is the most frequency a because it has more frequency I think I'm not that sure

Answer:

true i believe

Explanation:

Answer:

true

Explanation:

true because other guy said it lol

If the acceleration constant..

you can use the formula s = ut + 1/2at²

Known that :

s = ?

u = 0

t = 2s

a = 10ms-²

Then you can apply the formula

s = ut + 1/2at²

s = 0 + 1/2(10)(2)²

s = 5 × 4

s = 20m

Answer : 20m

Explanation :

The gravity can be 9,8 or 10. Also im not sure how people teach you but in my school, if the ball goes down the gravity is positive and not negative thats why i put 10ms-² and not -10ms-²

s = displacement/distance

u = initial speed

a = acceleration

t = time

sorry if im wrong

Answer:

6.77m/s

Explanation:

Using the law of conservation of momentum

m1u1 + m2u2 = (m1+m2)v

m1 and m2 are the masses of the object

u1 and u2 are the velocities before collision

v is the final collision

Given

m1 = 300g  = 0.3kg

u1 = 6.0m/s

m2 = 10g = 0.01kg

u2 = 30m/s

Required

The bird's speed immediately after swallowing v

Substitute the given values into the formula

m1u1 + m2u2 = (m1+m2)v

0.3(6) + 0.01(30) = (0.3+0.01)v

1.8+0.3 = 0.31v

2.1 = 0.31v

v = 2.1/0.31

v = 6.77m/s

Hence the bird's speed immediately after swallowing is 6.77m/s

Answer:

v = 340 m/s

Explanation:

Given that,

A herdsman yelling out to a fellow herdsman heard his voice reflected by a cliff 4s later.

The cliff is 680 m away

We need to find the velocity of sound in air.

Velocity = distance/time

Distance = 2 × 680 = 1360 m

[tex]v=\dfrac{1360\ m}{4\ s}\\\\=340\ m/s[/tex]

So, the velocity of sound in air is 340 m/s.

Answer:

The speed of the passengers is 5.24 m/s

Explanation:

Uniform Circular Motion

It occurs when an object in a circular path travels equal angles in equal times.

The angular speed can be calculated in two different ways:

[tex]\displaystyle \omega=\frac{v}{r}[/tex]

Where:

v = tangential speed

r = radius of the circle described by the rotating object

Also:

[tex]\omega=2\pi f[/tex]

Where:

f = frequency

Since the frequency is calculated when the number of revolutions n and the time t are known:

[tex]\displaystyle f=\frac{n}{t}[/tex]

The Ferris wheel has a diameter of 100 m and makes n=1 rotation in t=60 seconds, thus the frequency is:

[tex]\displaystyle f=\frac{1}{60}\ Hz[/tex]

The angular speed is:

[tex]\displaystyle \omega=2\pi \frac{1}{60} =\frac{\pi}{30} \ rad/s[/tex]

Now we calculate the tangential speed, solving this formula for v:

[tex]\displaystyle \omega=\frac{v}{r}[/tex]

[tex]v=\omega . r[/tex]

The radius is half the diameter, r=100/2=50 m:

[tex]\displaystyle v=\frac{\pi}{30} . 50[/tex]

Calculating:

v = 5.24 m/s

The speed of the passengers is 5.24 m/s

A ripcord system pulls a closing pin, which releases a spring-loaded pilot chute, and opens the container; from which the parachute comes out.

If a skydiver is unable to open her/his parachute, an automatic activation device will automatically open the parachute.

A parachute works by forcing air into the front of it and creating a structured 'wing' under which the canopy pilot can fly. Parachutes are controlled by pulling down on steering lines which change the shape of the wing, cause it to turn, or to increase or decrease its rate of descent.

Answer:

(a) the observed frequency is 200 Hz

(b) the observed frequency is 188 Hz.

Explanation:

speed of the truck, Vs = 27 m/s

frequency of the truck as it approaches, Fs = 185 Hz

(a) Apply Doppler effect to determine the frequency you will hear.

As the truck approaches you, the observed frequency will be higher than the source frequency because of decrease in distance.

[tex]F_s = F_o [\frac{V}{V_S + V} ][/tex]

Where;

Fo is the observed frequency which is the frequency you will hear.

V is speed of sound in air

[tex]F_s = F_o [\frac{V}{V_S + V} ]\\\\185 = F_o [\frac{340}{27 + 340} ]\\\\185 = F_o (0.926)\\\\F_o = \frac{185}{0.926}\\\\F_o = 199.78 \ Hz[/tex]

[tex]F_o = 200 \ Hz[/tex]

(b) Apply the following formula for a moving observer and a moving source;

[tex]F_o = F_s[\frac{V-V_o}{V} ](\frac{V}{V-V_S} )[/tex]

The observed frequency is negative since you are driving away from the truck and the source frequency is also negative since it is driving towards you.

[tex]F_o = F_s[\frac{V-V_o}{V} ](\frac{V}{V-V_S} )\\\\F_o = 185[\frac{340-22}{340} ](\frac{340}{340-27} )\\\\F_o = 185(0.9353)(1.0863)\\\\F_o = 188 \ Hz[/tex]

Answer:

B. Planet X, because its line has the greater slope.

Explanation:

In a speed graph, acceleration is slope. A greater slope means a greater acceleration. According to Newton's 2nd law (F=mg), a greater acceleration means a greater force.

Planet X exerts the greater force of gravity on the sphere, because its line has the greater slope. Hence option B is correct.

Gravitational force is force of attraction between two masses. Gravitational force(F) between two bodies is directly proportion to the product of masses(m₁,m₂) of two bodies and inversely proportional to square of distance(r) between them. mathematically it is written as,

F ∝ m₁.m₂

F ∝ 1/r²

F = G m₁,m₂÷r²

where G is gravitational constant, whose value is 6.6743 × 10⁻¹¹ m³ kg-1s⁻².

Force is expressed in Newton N in SI unit. its dimensions are [M¹L¹T⁻²].

This is analogous with coulomb's law which gives force between two charges.

if a planet has greater gravitational force(force of gravity), then body falls with greater speed as compare to other planet which is having less force of gravity. we can see in case of planet X there is greater speed as compare to plane Y in short time. Hence option B is correct.

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#SPJ2.

D) Speed, direction, or both

Mass doesn’t just CHANGE like that.

Answer:

A) 5 m/s/s

Explanation:

Given the following data;

Initial velocity = 10m/s²

Final velocity = 20m/s²

Time, t = 2 seconds.

In physics, acceleration can be defined as the rate of change of the velocity of an object with respect to time.

This simply means that, acceleration is given by the subtraction of initial velocity from the final velocity all over time.

Hence, if we subtract the initial velocity from the final velocity and divide that by the time, we can calculate an object’s acceleration.

Mathematically, acceleration is given by the equation;

[tex]Acceleration, a = \frac{final \; velocity - initial \; velocity}{time}[/tex]

Substituting into the equation, we have;

[tex]Acceleration, a = \frac{20 - 10}{2}[/tex]

[tex]Acceleration, a = \frac{10}{2}[/tex]

Acceleration, a = 5m/s²

Complete question

The diagram for this question is shown on the first uploaded image

Answer:

The largest possible distance is [tex]e = 15.33 \ m[/tex]

Explanation:

From the question we are told that

   The separation between Speaker at  position  A and B  is  AB =  6.60 m

   The frequency of the tune which the speaker are playing is [tex]f = 126 \ Hz[/tex]

    The speed of sound is [tex]v = 343 \ m/s[/tex]

Generally the wavelength of the tune playing is mathematically represented as

           [tex]\lambda = \frac{v}{f}[/tex]

=>        [tex]\lambda = \frac{343}{ 126}[/tex]

=>        [tex]\lambda = 2.72 \ m[/tex]

Let the observer be at position D

Generally the distance A and  is mathematically  evaluated using  Pythagoras theorem as

       [tex]AC = \sqrt{AB ^2 + BC^2}[/tex]

Let BC = e

So  

       [tex]AC = \sqrt{6.60 ^2 + e^2}[/tex]

Generally the path difference between the first and the second speaker from the observer point of view is mathematically represented as

       [tex]P = AC - BC[/tex]

=>     [tex]P = \sqrt{6.60 ^2 + e^2} - e[/tex]

Generally the condition for destructive interference is mathematically represented as

            [tex]P = (2n - 1 )\frac{\lambda}{2}[/tex]

Here n is the order of the fringe which is  one

=>        [tex]\sqrt{6.60 ^2 + e^2} - e = (2 * 1 - 1 )\frac{2.72}{2}[/tex]

=>        [tex]\sqrt{6.60 ^2 + e^2} - e = 1.36[/tex]

=>        [tex]6.60 ^2 + e^2 =( 1.36 +e)^2[/tex]

=>        [tex]6.60 ^2 + e^2 =1.8496 + 2.72e +e^2[/tex]

=>          [tex]e = 15.33 \ m[/tex]

My opinion about friction is that It always acts in the opposite direction as the motion of the object.

Friction refers to the resistance of motion of one object that is moving relative to another object. Fricton has many application but it has also many disadvantages.

So we can conclude that friction is always acts in the opposite direction as the motion of the object.

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Answer:

The Greeks had drama and arts competitions that were considered very popular, and important in society.

Explanation:

hope it helps!

Answer:

F=4500N

Explanation:

F=m×g

F=1500kg×3m/s²

F=4500N

Answer:

F=4500N

Explanation:

F=m×g

F=1500kg×3m/s²

F=4500N

Answer:

it implies our universe is expanding