psychology: Echoic sensory memory is used when a lightning bolt flashes across the sky. Please select the best answer from the choices provided T F

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.

Learn more about friction here: https://brainly.com/question/24338873

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 Though modern craft are much more advanced and capable than that early model, Conventional Aircraft have been superseded in modern times by the AeroSpace Fighter, which can operate in both atmosphere and space.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:

1.62 m/s

Explanation:

Wavelength of the water wave= 54 m

The frequency is 0.03 Hz

Therefore the velocity can be calculated as follows

Velocity= frequency × wavelength

= 0.03 × 54

= 1.62 m/s

Answer:

i think it's d

Explanation:

Answer:

D

Explanation:

i feel like this one is it

Answer:

I guess the Ans for second one is gravitational force

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:

3.333 m/s^2

Explanation:

50/15 = 3.33 m/s^2

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:

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:

(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:

P = 3.3075 x 10⁶ N/m² = 479.71 lb/in²

Explanation:

In order to find the pressure , we first need to find the force exerted by the lady. The force must be equal to the weight of the lady:

Force = F = Weight = mg

F = mg = (54 kg)(9.8 m/s²)

F = 529.2 N

Now, we convert area to S.I unit:

Area = A = (1.6 cm²)(1 m/100 cm)²

A = 1.6 x 10⁻⁴ m²

Now, the pressure can be calculated as:

Pressure = P = F/A

P = 529.2 N/1.6 x 10⁻⁴ m²

P = 3.3075 x 10⁶ N/m²

Now, we convert this into lb/in²:

P = (3.3075 x 10⁶ N/m²)[(0.000145038 lb/in²)/(1 N/m²)

P = 479.71 lb/in²

Answer:

true i believe

Explanation:

Answer:

true

Explanation:

true because other guy said it lol

Answer:

The change in length per unit length per degree rise in temperature of copper is 0.000017k

Explanation:

Given that :

The linear expansivity of copper is 0.000017k. This simply means that ; for a given copper length, the length of such copper will increase by 0.000017k for every degree rose in temperature of the copper rod.

Therefore, the change in length per unit length per degree rise in temperature (k) is 0.000017

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:

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

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:

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

Explanation:

hope it helps!

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:

The block hits the ground at 27.9 m/s

Explanation:

Gravitational Potential Energy (GPE)

It's the energy stored in an object because of its height in a gravitational field.

It can be calculated with the equation:

U=m.g.h

Where m is the mass of the object, h is the height with respect to a fixed reference, and g is the acceleration of gravity or [tex]9.8 m/s^2[/tex].

When the block is at the edge of the cliff it has potential energy that can be transformed into any other type of energy as it starts falling to the ground.

The GPE of the block of mass m=42 Kg at h=40 m is:

U = 42*9.8*40

U = 16,464 J

The block loses 81 J due to air resistance, thus the energy stored when it hits the ground is 16,464 J - 81 J = 16,383 J.

This energy is stored as kinetic energy, whose formula is:

[tex]\displaystyle K=\frac{1}{2}mv^2[/tex]

Solving for v:

[tex]\displaystyle v=\sqrt{\frac{2K}{m}}[/tex]

[tex]\displaystyle v=\sqrt{\frac{2*16,383 }{42}}[/tex]

[tex]v=\sqrt{780.143}[/tex]

v = 27.9 m/s

The block hits the ground at 27.9 m/s

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:

Nasopharynx

Explanation:

The nasopharynx is posterior to the nasal cavity and serves only as a passageway for air.

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

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

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

D) Speed, direction, or both

Mass doesn’t just CHANGE like that.

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:

so true though

Explanation: