How fast is a skateboarder traveling if she travels 2 miles in 4 hours?​

Answer:

0.3 seconds approximately

Explanation:

Given that the height of the building is 55.9 m and cement block accidentally falls from rest from the edge of a 55.9-m-high building. The initial velocity of the block will be equal to zero. The final velocity will be achieved by using the formula:

V^2 = U^2 + 2gH

Where g = 9.8 m/s^2

H = 55.9m

V^2 = 0 + 2 × 9.8 × 55.9

V^2 = 1095.64

V = sqrt(1095.64)

V = 33.1 m/s

The velocity When the block is 11.2 m above the ground will be 33.1 m/s and the height h = 11.2 - 1.7 = 9.5 m

The time of escape can be calculated by using the formula;

h = Ut + 1/2gt^2

9.5 = 33.1t + 1/2 × 9.8 × t^2

9.5 = 33.1t + 4.9t^2

4.9t^2 + 33.1t - 9.5

By using quadratic formula to calculate the time, the negative value is ignored and the positive values will be the time the man has to get out of the way.

Please find the attached file for the remaining solution.

Answer:

wavelength = speed/frequency

Explanation:

Required

Determine which of the options can be used to calculate frequency

The relationship between wavelength, speed and frequency is as follows;

[tex]Frequency = \frac{Wave\ Speed}{Wave\ Length}[/tex] ---- Equation 1

When option (1), (2) and (4) are rearranged, they do not result in the above formula; only option (3) does

Checking option (3)

[tex]Wave\ Length = \frac{Speed}{Frequency}[/tex]

Multiply both sides by Frequency

[tex]Wave\ Length * Frequency = \frac{Speed}{Frequency} * Frequency[/tex]

[tex]Wave\ Length * Frequency = Speed[/tex]

Divide both sides by Wave Length

[tex]\frac{Wave\ Length * Frequency}{Wave\ Length} = \frac{Speed}{Wave\ Length }[/tex]

[tex]Frequency = \frac{Speed}{Wave\ Length }[/tex] --- Equation 2

Comparing equation 1 and 2; both equations are the same.

Hence, option (3) answers the question

Answer:

wavelength = speed/frequency

Explanation:

Required

Determine which of the options can be used to calculate frequency

The relationship between wavelength, speed and frequency is as follows;

---- Equation 1

When option (1), (2) and (4) are rearranged, they do not result in the above formula; only option (3) does

Checking option (3)

Multiply both sides by Frequency

Divide both sides by Wave Length

--- Equation 2

Comparing equation 1 and 2; both equations are the same.

Hence, option (3) answers the question

Answer:

Wright can be measured in pounds

Explanation:

Mass is the quantity of matter a body contains while weight is the measure of mass of a body. Weight is the product if mass and the acceleration due to gravity of a body.

If the mass of an object is known, we can determine the equivalent weight of such object and vice versa using the relationship W = mg

m is the mass if the object (in kg)

W is the weight

g is the acceleration due to gravity

g can be measured both on metre/seconds or lb/ft². This means that the weight of an object can be measured in both kgm/s² (Newton) and lb(pounds).

Also note that different object have different masses hence it is not always true to say that a bowling ball has the same mass as a golf ball.

Based on the explanation above, it can be concluded that Weight can be measured in pounds which gives the only correct statement.

Answer:

Weight can be measure in pounds

Explanation:

Answer:

Get your recommenders to mention diverse achievements. ...

Help your recommenders with relevant info. ...

The letter should always include examples of things you did. ...

The letter should show how you improved over time. ...

The tone of the letter should not be too dry.

Answer:

Average speed = 26.67 km/h

Explanation:

It is given that,

The first half of the journey by a body is traveled with a speed of 40 km/h and the next half is covered with a speed of 20 km/h

We need to find the average speed of the whole journey.​ When two speeds are given, the average speed is given by :

[tex]v=\dfrac{2v_1v_2}{v_1+v_2}\\\\v=\dfrac{2\times 40\times 20}{40+20}\\\\v=26.67\ km/h[/tex]

So, the average speed of the body of the whole journey is 26.67 km/h.

Answer:

36km/h

Explanation:

since the acceleration of the train was 0.5m/s² i.e it is constant . since the acceleration is constant you can use one of the "SUVAT" equations to find the answer.

the equation that best fits this question is: v²=u² + 2āS.

v stands for final velocity

u stands for intial velocity

v²=u² + 2āS since the car started from rest the intial velocity is zero.

v²=u² + 2āS

v²= 0 + 2(0.5m/s²)*100m

v²= 1m/s²*100m

√v²=√100m²/s²

v=10m/s

1km/hr = 1/3.6m/s

x. = 10m/s.

use criss cross method to find the value of x

x=( 1km/hr* 10m/s)

1/3.6m/s

x= 36km/hr

Answer:

he weight vector approaches the point within the mass, the equilibrium becomes unstable

any change in the conditions of the environment can cause the rock to slide

Explanation:

In general, a rock in a mountain is in stable equilibrium with the help of the force of gravity that causes its weight to be within the center of mass, that is, the weight vector is first and then it is electing the center of mass.

When for some reason the weight vector approaches the point within the mass, the equilibrium becomes unstable, and any change in the conditions of the environment can cause the rock to slide, for example a rain that reduces the friction force.

It may happen that the weight vector is after the center of the hubs, in this case there is an unstable balance and the stone is held in place by the force of friction with the environment that surrounds it, if this friction decreases the rock will slide .

Answer:

Rmmbr... Absolute gravity means zero gravity..

No, and we don't have a zero gravity environment in space, either.

On the ISS, gravity is very much working. Here on the surface, we experience an acceleration of gravity of about 9.81 m/s^2. On the space station they experience a slightly reduced acceleration (about 9.2 m/s^2) because of their increased distance from the center of the Earth (gravity is a 1/r^2 law).

What we are actually experiencing on the ISS is a state of free-fall. Gravity is pulling the astronauts down, just as if they had stepped out of an airplane, but it is also pulling the ISS down. We feel weight on the ground because gravity pulls us down and the ground, not wanting to move, pushes back up at us.

We call the environment on the ISS weightlessness. An astronaut could stand on a scale and appear to have no weight because the scale is falling, too, and therefore can't push back up at us.

The two ways that we best simulate this environment on the Earth is by using airplanes that fly in (approximately) parabolic paths to put the inhabitants and vehicle into free-fall and by working in swimming pools where the neutral buoyancy feels similar to being in free-fall.

Answer:

A. Mass

Explanation:

Answer:

Weight

Explanation:

Answer:

The terms of biosafety in a laboratory require that the person must not have the eyes and skin exposed.

Explanation:

A corrosive substance is a substance that can damage a surface when they come into contact.

These substances represent a danger in people since they can burn the eyes, the skin, and the inside of the body since the inhalation of gases can burn the respiratory tract.

These chemical burns can be avoided by properly following the biosafety protocol that a laboratory requires the use of masks, goggles, gloves, and an apron or lab coat.

Answer:

The answer is 631.157

Explanation:

The question requested that the answer to the subtraction of 26.543 from 657.70 must be written using significant figures.

Here are a few tips about how to Identify significant figures.

1) It should be noted that the number "0" is what is usually (but not always) affected while trying to identify significant figures. Hence, all other numbers/digits are always significant. For example, 26.543 has five significant figures.

2) The zeros found between these "other numbers/digits" are also significant. For example, 2202 has four significant figures.

3) In the case of a decimal, the tailing zeros or the final zero is also significant. 657.70 and 657.07 have five significant figures.

Now, back to the question

657.70  - 26.543  = 631.157.

Our final answer does not have a zero, hence all the digits (six) are significant.

Answer:

= 7.88 × 10^-12 T

Explanation:

From the above question, we are told that:

Kinetic Energy of the proton is K. E = 10.0 MeV

Step 1

We convert 10.0 MeV to Joules

1 Mev = 1.602 × 10-13 Joules

10.0 MeV = 10.0 × 1.602 × 10^-13 Joules = 1.602 × 10^-12 J

Hence, the Kinectic energy of a proton = 1.602 × 10^-12 J

Step 2

Find the Speed of the Proton

The formula for Kinectic Energy =

K.E = 1/ 2 mv²

Where

m = mass of the proton

v = speed of the proton

K.E of the proton = 1.602 × 10^-12 J

Mass of the proton = 1.6726219 × 10^-27 kilograms

Speed of the proton = ?

1.602 × 10^-12J = 1/2 × 1.6726219 × 10^-27 × v²

1.602 × 10^-12J = 8.3631095 ×10^-28 × v²

v² = 1.602 × 10^-12/8.3631095 ×10^-28

v = √(1.602 × 10^-12/8.3631095 ×10^-28)

v = 43772331.227m/s

v = 4.3772331227 × 10^7m/s

Approximately = 4.4 × 10^7 m/s

Step 3

Find the Magnetic Field of that region of space

The formula for Magnetic Field =

B = m v / q r

We are told that the proton executes a circular orbit, hence,

mv = √2m(KE)

m = Mass of the proton = 1.6726219 × 10^-27 kg

K.E of the proton = 1.602 × 10^-12 J

v = speed of the proton = 4.4 × 10^7 m/s

q = Electric charge = 1.6 × 10^-19 C

r = radius of the orbit = 5.80Ã10^10 m

= 5.8 × 10^10m

Magnetic Field =

=√ (2 × 1.6726219 × 10^-27 kg × 1.602 × 10^-12 J) /( 1.6 × 10^-19 C × 5.80 × 10^10 m)

= 7.88 × 10^-12 T

The magnetic field in that region of space is approximately 7.88 × 10^-12 T

Answer:

260

Explanation:

The average speed for the remaining time of the journey is 260 km/h.

The average speed of any moving object is the ratio of the total distance covered and the total time taken to cover that distance.

Given is a plane took 7 hours to travel 2020 km. For the first 4 hours,

it travelled at an average speed of 310 km/h.

Average Speed S1= distance /time

310 km/h = d/4

d = 1240 km

The remaining distance will be

2020 - 1240 = 780 km

The remaining hours are 7 - 4 =3 h

The average speed for the remaining distance is

Avg speed S2= 780 / 3

S2 = 260 km/h

Thus, the average speed of the car for the remaining is 260 km/h.

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Answer:

1.25 m

0.5 s

Explanation:

Given:

v₀ = 5 m/s

v = 0 m/s

a = -10 m/s²

Find: Δy

v² = v₀² + 2aΔy

(0 m/s)² = (5 m/s)² + 2 (-10 m/s²) Δy

Δy = 1.25 m

Find: t

v = at + v₀

(0 m/s) = (-10 m/s²) t + (5 m/s)

t = 0.5 s

Answer:

C. Ask questions about the world

Explanation:

A scientist is a person who conducts scientific research and provide scientific proves on the area of their interest such as physica, chemistry, biology or history.

A scientist gives the answers of the question about the world based on their scietifc research such as how does plant breath? effects of global warming on earth? what if we don't drink water for a particular time period? et-cetera.

Hence, the correct option is "C. Ask questions about the world".

Answer:

It becomes profane as a result of desacralization

Explanation:

Because desacralization means when a dedicated religious structure is no longer used for its intended purpose both rather used for another purpose other than the original purpose

Answer:

Option C. 4.5 A

Explanation:

We'll begin by calculating the equivalent resistance of R1 and R3. This can be obtained as follow:

R1 = 6 Ω

R3 = 3 Ω

Equivalent of R1 and R3 =?

Since R1 and R3 are in parallel connections, we shall their equivalence as follow:

Equivalent of R1 and R3 = (R1×R3) /(R1 + R3)

Equivalent of R1 and R3 = (6×3)/(6+3)

Equivalent of R1 and R3 = 18/9

Equivalent of R1 and R3 = 2 Ω

Next, we shall determine the equivalent resistance in the circuit.

This is illustrated below:

R2 = 2 Ω

Equivalent of R1 and R3 = 2 Ω

Equivalent resistance (R) in the circuit =?

Note: Equivalent of R1 and R3 is in series connection with R2.

Equivalent Resistance (R) = (Equivalent of R1 and R3) + R2

Equivalent Resistance (R) = 2 + 2

Equivalent Resistance (R) = 4 Ω

Finally, we shall determine the total current in the circuit as follow:

Potential difference (V) = 18 V

Equivalent Resistance (R) = 4 Ω

Current (I) =.?

From ohm's:

V = IR

Where V is the potential difference.

I is the current.

R is the resistance.

V = IR

18 = I × 4

Divide both side by 4

I = 18/4

I = 4.5 A

Therefore, the total current in the circuit is 4.5 A.

Answer:

speed = 50 metres/minute

Explanation:

Distance traveled = 100 metres

Time taken =- 2 minutes

Speed =[tex]\frac{Distance }{Time}[/tex]

speed =[tex]\frac{100}{2}[/tex]

speed = 50 metres/minute

The speed of a bird that flies 100 meters in 2 minutes is 0.83 m/s.

The speed is a scalar magnitude defined as the quotient of the distance traveled and the time, as follows:  

[tex] s = \frac{d}{t} [/tex]

Where:

d: is the distance = 100 m

t: is the time = 2 min

Hence, the bird's speed is:

[tex] s = \frac{d}{t} = \frac{100 m}{2 min} = 50 \frac{m}{min}*\frac{1 min}{60 s} = 0.83 m/s [/tex]

Therefore, the bird's speed is 0.83 m/s.

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I hope it helps you!

Answer:

we can say that that in an increasing order, the body is less dense than the glycerine, and the glycerine is less dense than the kerosene.

Explanation:

If the body sinks below the kerosene level to float in glycerine, then it means that the kerosene is denser than glycerine. This is because bodies will float higher in a denser fluid that a less denser fluid. Also, since the body floats in kerosene and glycerine, then the body is less dense than the kerosene and the glycerine. Finally, we can say that that in an increasing order that the body is less dense than the glycerine, and the glycerine is less dense than the kerosene

Answer: A) Had twice as much mass

Explanation:

Given that the force of gravity pulling down on school = 400,000 N

The force of force of gravity is the product of mass of the body and the acceleration due to gravity. The acceleration due to gravity is constant on the earth surface with a constant value of 9.8m/s²

Hence,

F = mg = 800N

F = force of gravity, m = mass of body, g =! acceleration due to gravity.

since g is constant, to have 2F, then mass has to be doubled, that is 2m(2 * mass)

Answer:

I think lead is the heaviest one

Answer:

protons

Explanation:

the protons identifies an atoms as that of a particular element the atomic number is equal to the number of protons in the nucleus of an atom

The sound signal helps to caution and let other people know the exact

position or location during sailing in limited visibility conditions.

Sailors are in which charge of controlling and movement of ships. In limited

visibility conditions such as during fogs, one prolonged blast plus two short

blasts every two minutes are done.

This helps to alert people and other sailors of their location at sea to prevent

accidents and death.

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The sound signal helps to know the exact location during sailing in foggy conditions.

Sailors are the in charge of controlling and movement of ships. In limited visibility conditions such as fogs, one prolonged blast plus two short blasts every two minutes are done.

This helps to caution people and other sailors around their location at the sea to prevent accidents and death.

Learn more about Sailors

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Explanation:

The momentum of any object is given by the product of mass and velocity with which it is moving i.e.

p = mv

Momentum is a vector quantity. It means we can resolve it into rectangular components.

If the car is moving with a speed of 20 m/s in North direction, its momentum is given by :

[tex]p_y=20m\ \hat{j}\ kg-m/s[/tex] .....(1)

If the car is moving with a speed of 20 m/s in East direction, its momentum is given by :

[tex]p_x=20m\ \hat{x}\ kg-m/s[/tex] ....(2)

It is clear from equation (1) and (2) that the magnitude of momentum is same but the direction of momentum is different in both cases.

Answer:

The time taken for the sound wave to make the round trip is 0.16 s.

Explanation:

Given;

distance traveled by the sound wave, d = 120 m

bulk modulus of sea water, B = 2.3 x 10⁹ N/m²

density of sea water, ρ = 1022 kg

The speed of the wave is given by;

[tex]v = \sqrt{\frac{B}{\rho} } \\\\v = \sqrt{\frac{2.3*10^9}{1022} }\\\\v = 1500.16 \ m/s[/tex]

Speed is given by;

[tex]Speed = \frac{Distance}{Time}[/tex]

total distance of the round trip = 2 x 120m = 240 m

Time taken for the sound wave to make the round trip is given by;

[tex]Time = \frac{Distance}{Speed} \\\\Time = \frac{240}{1500.16} \\\\Time = 0.16 \ second[/tex]

Therefore, the time taken for the sound wave to make the round trip is 0.16 s.

Answer:

Proper weighting

Explanation:

Proper weighing involves the condition of a scuba diver that is fully geared having a near empty tank and the BCD emptied with a held breadth is expected to float at eye level

The fundamental of adequate or good buoyancy of a scuba diver is to ensure proper weighting when diving, With proper weighting, there is more control for the diver when a safety stop is required. There is less need to carry excess weight that increases drag and gas consumption.  

Answer:

Hey there!

They used math to explain their observations, for example, Newton is famous for his three laws, and universal laws of gravitation.

Let me know if this helps :)

Answer:

50 mph

Explanation:

doesn’t have direction

50 mph is not a velocity bcos it doesn't have direction