a cross country runner runs 10 km in 40 minutes. what is his average speed

Answer:

1. Which of the following actions is permissible when you are graphically adding one vector to another:

Explanation:

: move the vector, rotate the vector, change the vector's length?

When you graphically add one vector to another, you can only move the vector as long as you don't modify its length or the direction it points in.

In physics, a vector is a quantity with both a magnitude and a direction. It is often represented by an arrow whose length is proportional to the magnitude of the quantity and whose direction is the same as that of the quantity.

A vector does not have position, while having magnitude and direction. In other words, a vector's shape is unaltered if it is shifted parallel to itself as long as its length is unaltered.

Hence, when you are graphically adding one vector to another, permissible action is move the vector as long as you don't modify its length or the direction it points in.

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Explanation:

Position-time graphs measure/express the position of a skater over time relative to the start or finish of the race (depends on how it is used). Note: are the skaters in line vertically or horizontally? Like is one directly behind the other or are they next to each other?

If the two skaters are in line horizontally with each other, then their position will be the same relative to the start or finish of the race. This means if one passes the other one, the position would be different for all times after they pass. On the graph, it would look like one single line at the start (as position is same) which splits into 2 (representing the new difference in position due to 1 passing the other.

If the two skaters are in line vertically, their lines on the graph will appear parallel to each other (assuming they are going same speed) because the position is changing at the same rate, one is just reaching the same point after the other. If the skater behind overtakes the one in front. The lines on the graph will cross and continue either in parallel but with the other line on top to represent the moment where their position is the same right before they pass and after, where the second skater is now in front.

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Answer:

A machine is a mechanical structure that uses power to apply forces and control movement to perform an intended action.

Explanation:

Example: Elevator

Answer:

vacuole

Explanation:

Remember vacuoles in plant cells are a lot bigger than there animal cell counterparts.

Answer:

Accurate at 99.9999746%

Explanation:

First of all, let's calculate how many seconds we have in a year which has 365 days.

1day = 24 × 60 × 60 seconds = 86400 s

Thus, for 365 days, we have;

86400 × 365 = 31536000 seconds

Now, since 1 year has 31536000 seconds, let's find the ratio of efficiency.

We are told that the watch manufacturer claims that its watches gain or lose no more than 8 seconds in a year. Thus, efficiency is given by;

Efficiency = (8/31536000) × 100% = 0.00002536783 %

Thus, it will be be accurate at;

100% - 0.00002536783% ≈ 99.9999746%

Answer:

11.025m

Explanation:

Using kinematics,

u = Initial velocity = 0.

t = Time taken = 1.5sec.

a = Acceleration from gravity = 9.8m/s^2

Distance = s

= ut + 1/2 * a * t^2

= 0 + 1/2 * 9.8 * (1.5)^2

= 11.025m

The egg fall from the nest of a tree is 11.025 m.

To find height from where the egg fall, the given values are:

Time taken t = 1.5 seconds.

By knowing the concept of Kinematics,

  For a particle moving with a constant acceleration, its displacement after a time period is given by

           s = ut +1/2 at²

where, u - initial velocity,

t - Time,

a - acceleration.

As u is the Initial velocity = 0.

t = 1.5s

Acceleration from gravity = 9.8m/s²

Here, Distance = s

Substituting all the values in the formula,

s = ut + 1/2 ( a × t²)

  = 0 + 1/2 × 9.8 × (1.5)²

Distance s = 11.025m

So, the distance the egg fall from a nest of a tree is s = 11.025 m.

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The correct answer is A. He created a way of naming organisms based on genus and species

Explanation:

Carl Linnaeus created a simple but precise system for naming organisms of any species and kind. This system was known as binomial nomenclature and the names of organisms depend on two main elements: the genus and the species. The first element is a broad category that covers species with a common origin, and the second one is the species, which describes organisms that can reproduce and share many common features including DNA sequence. According to this, the correct answer is A.

Explanation:

Acceleration is change in velocity over time.

a = (v − v₀) / t

a = (0.00 m/s − 9.00 m/s) / 5.00 s

a = -1.80 m/s²

Answer:What is the acceleration of a car that moves from rest to 15.0 m/s in 10.0 s? Vi=0, vf= 15.0 m/s,t=10.0s, a=? a= vf =vi/tA=15.0m/s-0m/s/10.0s = 15.0s/10.0s m/s*1/s =1.50 m/s^2 11.

Explanation:

Answer:

Distance = 30 m

Explanation:

Since the position of the bus is at zero, and distance is a scalar quantity. That is, we are only concerned about the magnitude

If Angela ran to the bus and back to where she started, the distance travelled will be:

Distance = 15 + 15 = 30 m

But her displacement will be:

Displacement = 15 - 15 = 0.

The force exerted by a magnet is called The push or pull of magnetism can act at a distance, which means that the magnet does not have to touch an object to exert a force on it. ... In fact, magnetism is the result of a moving electric charge.Explanation:

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1. Heat causes magnetic bodies to lose their magnetic force. For each material of magnet, there is a Curie temperature, or temperature at which the heat will destroy the polarization of the material, causing it to loses its magnetic properties.

2. In unmagnetized materials the domains are randomly aligned in different directions and cancel each other out. In a magnet, all the domains are oriented in the same direction. In the case of a nail, the domains can be aligned in the same direction causing the nail to become magnetic.

3. because after got attracting they will also got act as magnets since they would also get North and South poles so in the case of same poles they had repulsion.

4. We know that magnetic fields exert forces on moving electrons for example. ... When you are in the middle of the magnet, the metal object is being pulled more or less equally in both directions, and so the result is that the object doesn't really feel a force in either direction, they cancel each other out.

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Answer:

Its is because plants dont get sugar from eating food so, they need chloroplast to make food with the help of sunlight.Whereas animal can get sugar from the food they eat.

Answer:

Please find the answer in the explanation

Explanation:

Given that some plants were watered with 4 different types of water (salt water, regular water, sugar water and distilled water). After a two-week period, the height of the plants is measured.

1.) The Independent Variable (IV) are the different types of water

2)Dependent Variable (DV) are the height of the plant. Dependent variable depends on the independent variable.

3)Constant is the unchanged parameter which is the period - the two weeks

4)Control: is the quantity of water used.

Answer:

2.7

Explanation:

[tex]Force = 25N\\mass = 9 kg\\acceleration = ?\\\\Force = mass \times acceleration\\\frac{Force}{mass}= acceleration\\ \\Acceleration = \frac{25}{9} \\\\Acceleration = 2.7[/tex]

Answer:

Matthew should use the safety glasses as his PPE.

Explanation:

Answer:

The point at which the electrical potential is zero is x = +0.33 m.

Explanation:

By definition the electrical potential is:

[tex] V_{E} = \frac{K*q}{r} [/tex]

Where:

K: is Coulomb's constant = 9x10⁹ N*m²/C²

q: is the charge

r: is the distance

The point at which the electrical potential is zero can be calculated as follows:

[tex] V_{1} + V_{2} = 0 [/tex]

[tex] K(\frac{q_{1}}{r_{1}} + \frac{q_{2}}{r_{2}}) = 0 [/tex]    (1)

q₁ is the first charge = +3 mC

r₁ is the distance from the point to the first charge  

q₂ is the first charge = -6 mC

r₂ is the distance from the point to the second charge    

By replacing r₁ = 1 - r₂ into equation (1) we have:

[tex]K(\frac{q_{1}}{1 - r_{2}} + \frac{q_{2}}{r_{2}}) = 0[/tex]   (2)

By solving equation (2) for r₂:

[tex]r_{2} = \frac{q_{1}}{q_{1} - q_{2}} = \frac{3 mC}{3 mC - (-6 mC)} = +0.33 m[/tex]

Therefore, the point at which the electrical potential is zero is x = +0.33 m.

I hope it helps you!  

Since the two charges are placed on the x-axis. Then, the electric potential is zero at the distance of 0.66 m from the second point charge on the x-axis.

The electric potential at any point is the amount of work needed to move a unit positive charge from infinity to that point.

Given data-

The magnitude of a point charge is, Q = + 3 C.

The magnitude of the second point charge is, Q' = -6 C.

The distance between the two charges is, x = 1.0 m.

The expression for the net electric potential due to both the charges is,

[tex]V = \dfrac{k \times Q}{x} +\dfrac{k \times Q'}{x-y}[/tex]

here,

k is the Coulomb's constant.

y is the distance from the second point charge on the x-axis, where the net potential is zero.

Now, for zero net electric potential due to both the charges we have,

[tex]0 = \dfrac{k \times Q}{x-y} +\dfrac{k \times Q'}{y}\\\\\\-\dfrac{k \times Q'}{y}=\dfrac{k \times Q}{x-y}[/tex]

Solving as,

[tex]-\dfrac{(-6)}{y}=\dfrac{3}{1-y}\\\\6-6y=3y\\\\y =0.66\;\rm m[/tex]

Thus, we can conclude that the electric potential is zero at the distance of 0.66 m from the second point charge on the x-axis.

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Explanation:

Newton’s third law of motion states that every action has an equal and opposite reaction. This indicates that forces always act in pairs. Reaction forces are equal and opposite, but they are not balanced forces because they act on different objects so they don’t cancel each other out.

Answer:

[tex] \boxed{\sf Acceleration \ of \ the \ car = -5 \ m/s^2} [/tex]

Given:

Initial speed (u) = 30 m/s

Final speed (v) = 20 m/s

Time taken (t) = 2s

To Find:

Acceleration (a) of the car

Explanation:

From equation of motion we have:

[tex] \boxed{ \bold{v = u + at}}[/tex]

By substituting value of v, u & t in the equation we get:

[tex]\sf \implies 20 = 30 + a(2) \\ \\ \sf \implies 2a + 30 = 20 \\ \\ \sf \implies 2a = 20 - 30 \\ \\ \sf \implies 2a = - 10 \\ \\ \sf \implies a = - \frac{10}{2} \\ \\ \sf \implies a = - 5 \: m {s}^{ - 2} [/tex]

[tex] \therefore[/tex]

Acceleration (a) of the car = -5 m/s²

Answer:

Explanation:

Using the formula : E = mc²

Where m = mass = 6.8 × 10^-6 kg

c = speed of light = 3 ×10^8 m/s

The amount of joules of energy that would be produced equals :

Plugging in our values :

E = mc²

E = (6.8 × 10^-6) kg × (3 ×10^8)²m/s

E = (6.8 × 10^-6) kg × 9 × 10^16 m/s

E = 61.2 × 10^(-6 + 16)

E = 61.2 × 10^10 J

Answer:

E = 6.12 × 1011 kg × m2/s2

Explanation:

Answer:

platinum, iridium, osmium, iron, zinc

Answer:

50m [N]

Explanation:

Think of these directions as if they were on a 2D plane. (if you're talking about displacement)

If you go 32m [N] then 6m [S], it's like you're moving backwards (-). (thus, 32n-6s=26m [N])

Next, you go north again, so moving forwards (+). (thus, 26n+24n=50m [N])

The distance he paddled was (32m + 24m + 6m)  =  56 meters.

His displacement after that was (32m - 6m + 24m) = 50 meters north.

Answer:

B. Manipulated Variable

Answer:responding variable

Explanation:

Apex users

Answer:

the direction of acceleration of the vehicle is the same direction of its velocity of car

s acceleration has the opposite direction to the car speed.

Explanation:

The initial acceleration of the car can be calculated with

          v = v₀ + a t

          a = (v-v₀) t

indicate that the initial velocity is zero (v₀ = 0 m / s)

         a = v / t

         a = 300 / t

the direction of acceleration of the vehicle is the same direction of its acceleration movement.

When the car collides with the wall, it exerts a force in the opposite direction that stops the vehicle, therefore this acceleration has the opposite direction to the car speed. But your module must be much larger since the distance traveled to stop is small

Answer:

I believe that it's True.

Answer:

Explanation:

This problem is on the capillary action of water and tube

we are going use the formula below for the rise in liquid level

where h= height of liquid level in the capillary tube

          T= surface tension = 0.073 Nm

          ∅= angle of contact = 60 degrees

          r= radius of bore of capillary tube = 5/2= 2.5 mm to m= 2.5/1000=  

          2.5*10^-3

          g= acceleration due to gravity = 9.81 m/s^2

         ρ= density of the liquid (assume water 1000 kg/m³)

we can now substitute to solve for h

[tex]h=\frac{2*0.073cos60}{ 2.5*10^-^3*9.81*10^3} \\\\h=\frac{2*0.073*0.5}{ 2.5*9.81}\\\\h=\frac{0.073}{ 2.5*9.81}\\\\h=\frac{0.073}{ 24.525}\\\\h=\frac{0.073}{ 24.525}\\\\h= 0.0029\\h= 2.9*10^-^3mm[/tex]

Answer:

A example of a scientific way of thinking is making observations, forming questions, making hypotheses, doing an experiment, analyzing the data, and forming a conclusion.

Answer:

Statistics

Explanation: