This is my question ​

Answer:

The average speed is 22.2 km/h

Explanation:

Average Speed

Given an object travels a total distance d and took a total time t, then the average speed is:

[tex]\displaystyle \bar v=\frac{d}{t}[/tex]

The mailman first drives d1=7 km at v1=15 km/h. The time taken to drive is:

[tex]\displaystyle t1=\frac{d1}{v1}=\frac{7}{15}=0.467\ h[/tex]

Then he drives d2=7 km at v2=43 km/h taking a time of:

[tex]\displaystyle t2=\frac{d2}{v2}=\frac{7}{43}=0.163\ h[/tex]

The total time is

t=0.467 h + 0.163 h = 0.63 h

The total distance is

d = 7 km + 7 km = 14 km

The average speed is:

[tex]\displaystyle \bar v=\frac{14}{0.63}=22.2\ km/h[/tex]

The average speed is 22.2 km/h

Answer:

WHATATATATTAT

Explanation:

Answer:

record vibrations of earthquake

Answer:

[tex]\huge\boxed{\sf Option \ 2}[/tex]

Explanation:

Seismograph is an instrument with is used to record vibrations of earthquake.

Seismographs are basically used to detect seismic waves by which scientists can detect the earth's interior and also can find the depths of earthquakes and their intensity.

[tex]\rule[225]{225}{2}[/tex]

Hope this helped!

Answer:

32* acceleration

Explanation:

why? because if the ball is at a 35* angle then it will accelerate 32*

The acceleration of the golf at the maximum height is equivalent to acceleration due to gravity = 9.8 m/s².

The given parameters;

angle of projection of the ball, Ф = 45°

Acceleration is defined as the change in velocity per change in time of motion.

[tex]a = \frac{\Delta v}{\Delta t} = \frac{v_f }{t}[/tex]

where;

[tex]v_f[/tex] is the final velocity of the golf

At maximum height the final velocity of a projectile is zero (0)

The acceleration for upward motion becomes;

[tex]a = \frac{0 }{t} + g= g[/tex]

Thus, the acceleration of the golf at the maximum height is equivalent to acceleration due to gravity.

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Answer:

b

Explanation:

Answer:

36111 kg

Explanation:

Given

Force = 65000N

Acceleration = 1.8m/s²

Required

Determine the mass of the elevator

This question will be answered using the following Force formula.

Force = Mass * Acceleration

Substitute values for Force and Acceleration

65000N = Mass * 1.8m/s²

Make Mass the subject

Mass = 65000N/1.8m/s²

Mass = 36111.11 kg

From the list of given options, option E answers the question.

Answer:

B is correct

Explanation:

Maximum Kinetic energy= Work done.

Now, Work done=mgh=mg(L−Lcosθ)=mgL(1−cosθ)

Option B is thus correct.

Answer:

A. 29.7 m/s

B. 6.06 s

Explanation:

From the question given above, the following data were obtained:

Maximum height (h) = 45 m

A. Determination of the initial velocity (u)

Maximum height (h) = 45 m

Acceleration due to gravity (g) = 9.8 m/s²

Final velocity (v) = 0 m/s (at maximum height)

Initial velocity (u) =.?

v² = u² – 2gh (since the ball is going against gravity)

0² = u² – (2 × 9.8 × 45)

0 = u² – 882

Collect like terms

0 + 882 = u²

882 = u²

Take the square root of both side

u = √882

u = 29.7 m/s

Therefore, the ball must be thrown with a speed of 29.7 m/s.

B. Determination of the time spent by the ball in the air.

We'll begin by calculating the time take to reach the maximum height. This can be obtained as follow:

Maximum height (h) = 45 m

Acceleration due to gravity (g) = 9.8 m/s²

Time (t) to reach the maximum height =?

h = ½gt²

45 = ½ × 9. 8 × t²

45 = 4.9 × t²

Divide both side by 4.9

t² = 45/4.9

Take the square root of both side

t = √(45/4.9)

t = 3.03 s

Finally, we shall determine the time spent by the ball in the air. This can be obtained as follow:

Time (t) to reach the maximum height = 3.03 s

Time (T) spent by the ball in the air =?

T = 2t

T = 2 × 3.03

T = 6.06 s

Therefore, the ball spent 6.06 s in the air.

Answer:

big bang theory

Explanation:

Edwin Hubble is credited for the initial development of the Big Bang theory, an idea which helps to explain the formation of the universe over 15 billion years ago.

Answer:

Leave onions in cold water for about 15 minutes! Takes out the chemical reaction in the onion's defense system.

Explanation:

This is what people NEED to know for cooking... Lol :)

Answer:

If two particles are involved in an elastic collision, the velocity of the second particle after collision can be expressed as: v2f=2⋅m1(m2+m1)v1i+(m2−m1)(m2+m1)v2i v 2 f = 2 ⋅ m 1 ( m 2 + m 1 ) v 1 i + ( m 2 − m 1 ) ( m 2 + m 1 ) v 2 i .

Explanation:

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Answer:

Inertia; Newton's First Law

Explanation:

When you hit you're breaks, the force you feel that pulls you forward is due to inertia.

Newton's first law says that "every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force." The question is a perfect example of this.

It is due to the inertia of motion of the objects that they fall on the floor bed. This is also called Newton's first law of motion.

Newton's first law of motion is known as the law of inertia.

Given is a man who is driving a car at 35 mph hits his brakes suddenly in order to avoid hitting a dog. During the incident, everything in the front seat of his car slides forward and into the floorboard.

The property of body by virtue of which it resist any change in its state of rest or uniform motion is called inertia of body. When the car was moving at 35 mph, every object on front seat was also moving with the same speed. However, when the brakes were applied, they were applied on the car and not on the objects in the front seat. Hence, they keep moving forward and stop only when they strike and fall down. This is called inertia of motion. This is Newton's first law of motion.

Therefore, it is due to the inertia of motion of the objects that they fall on the floor bed. This is also called Newton's first law of motion.

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Answer:

This question is incomplete

Explanation:

This question is incomplete because the telescope's focal length was not provided. The formula to be used here is

Magnification = telescope's focal length/eyepiece's focal length

The eyepiece's focal length was provided in the question as 0.38 m.

NOTE: Magnification can be described as the power of an instrument (in this case telescope) to enlarge an object. It has no unit and thus the two focal lengths mentioned in the formula above must be in the same unit (preferably meters since one of them is in meters already).

Steps 1 and 2)

The variables are W = work, P = power, and t = time. In this case, W = 9514 joules and P = 347 watts.

The goal is to solve for the unknown time t.

-----------------------

Step 3)

Since we want to solve for the time, and we have known W and P values, we use the equation t = W/P

-----------------------

Step 4)

t = W/P

t = 9514/347

t = 27.4178674351586

t = 27.4 seconds

-----------------------

Step 5)

The lawn mower ran for about 27.4 seconds. I rounded to three sig figs because this was the lower amount of sig figs when comparing 9514 and 347.

-----------------------

Note: we don't use the mass at all

Answer:

E=mc2

Explanation:

It explains that in their interiors, atoms fuse together, creating energy.

To solve this we must be knowing each and every concept related to energy and its different types. Therefore, the famous equation that describes the energy of stars is E=mc².

In physics, energy is the capacity to accomplish work. It can be potential, kinetic, thermal, electric, chemical, radioactive, or in other forms.

There is also heat and work—energy inside the process of being transferred by one body to the other. Energy is always classified according to its type once it has been transmitted. As a result, heat transported could become thermal energy, whereas labor done may emerge as mechanical energy. The famous equation that describes the energy of stars is E=mc²

Therefore, the famous equation that describes the energy of stars is E=mc².

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Answer:

A. Oceanic crust is continually recycled through convection in the earth's mantle

Explanation:

The oceanic plate is constantly being recycled through the forces of convection within the earth's mantle.

New oceanic plate are formed mid-oceanic ridge for example. As the magma cools and solidifies, they are moved away continually.

This is not the case for the continental curst.

Answer:

The fish displacement was -3.4 m

Explanation:

Distance and Displacement

A moving object constantly travels some distance at defined periods of time. The total moved distance is the sum of each individual distance the object traveled. It can be written as:

dtotal=d1+d2+d3+...+dn

This sum is obtained independently of the direction the object moves.

The displacement only takes into consideration the initial and final points of the path defined by the object in its moving. The displacement, unlike distance, is a vectorial magnitude and can be even zero if the object starts and ends the movement at the same point.

The displacement, when the object moves in one axis only is given by:

d = final position - initial position

We know the fist started at 7.8 m from a given reference along the x-axis.

After some undisclosed movements, it ends up at the position 4.4 m. Thus, the displacement is:

d = 4.4 m - 7.8 m = -3.4 m

This means the fish ended up to the left of the position it started from.

The fish displacement was -3.4 m

Answer:

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Answer:

B

Explanation:

it could be because they have a difference in genes

Answer:

357 J

Explanation:

The elastic potential energy of arrow in the stretched bow is 357 J.

The kinetic energy of the arrow after it has been shot is given by half of the product of the arrow's mass and velocity of the arrow.

Here there are no other forms of energy at play here. Only potential and kinetic energy.

As we know that in any system the energy is conserved accordingly the elastic potential energy of the arrow will be equal to the kinetic energy of the bow after it is released i.e., 357 J.

Answer:

1.25

Explanation:

acceleration = velocity÷time

Answer:

Its acceleration is 1.25 meters/second2

Explanation:

The car's average acceleration would be 1.25m/s^2 or 1.25meters/second/second. That looks to be the fourth one you've listed.

Answer:

Answer is: c. It must lose two electrons and become an ion.

Magnesium (Mg) is metal from 2. group of Periodic table of elements and has low ionisation energy and electronegativity, which means it easily lose valence electons (two valence electrons).

Magnesium has atomic number 12, which means it has 12 protons and 12 electrons. It lost two electrons to form magnesium cation (Mg²⁺) with stable electron configuration like closest noble gas neon (Ne) with 10 electrons.

Electron configuration of magnesium ion: ₁₂Mg²⁺ 1s² 2s² 2p⁶.

Explanation:

Answer:

the third option

Explanation:

Answer:

Explanation:

According to law of conservation of momentum

m1u1+ m2u2 = (m1+m2)v

m1 and m2 are the masses of the object

u1 and u2 are their initial velocities

v is their common velocity

Given

m1 = 3kg

m2 = M

u1 = 8m/s

u2 = 0m/s (object at rest)

v = 6.0m/s

Substitute and get M

3(8) + M(0) = (3+M)6

24 = 18+6M

24-18 = 6M

6 = 6M

M = 1kg

Hence the mass M is 1kg

Answer:

angular speed = 67.91 rad/s

Explanation:

Given that,

The diameter of a tire, d = 72 cm

The radius of a tire, r = 36 cm = 0.36 m

Linear speed of an automobile, v = 88 km/h = 24.45 m/s

We need to find the angular speed of the tires about their axles. The relation between angular speed and angular speed is given by :

[tex]v=r\omega\\\\\omega=\dfrac{v}{r}\\\\\omega=\dfrac{24.45 }{0.36}\\\\\omega=67.91\ rad/s[/tex]

So, the angular speed of the tire is 67.91 rad/s.

Answer:

The electrostatic force will remain the same

Explanation:

From the question we are told that  

     The charge on the each conducting sphere is [tex]q = 2 \ C[/tex]

      The radius each sphere is [tex]r_1 = r_2 = r = 0. 1\ m[/tex]

Generally electrostatic force between the sphere is mathematically represented as

             [tex]F = \frac{k * q_1 q_2 }{d^2}[/tex]

Here  k is the coulomb constant ,

         d  is the distance between the two sphere which is measured from one center of the sphere to the other center of the sphere  

Now from the question we are told that the radius of the spheres is doubled (i.e  from 0.10 m  to 0.2 m ) , this will not affect the distance between the sphere because their center are still in the same position

and given there is no change in the distance between the spheres , the electrostatic force will remain the same

Answer:

+1

-1

Explanation:

The oxidation number of Na in NaCl is +1 and that of Cl is -1.

When NaCl is oxidized we have;

        NaCl →  Na⁺  + Cl⁻

In this process, Na will lose an electron to become Na⁺ and thus isoelectronic with Ne, Cl will gain the electrons to become Cl⁻ and thus isoelectronic with Argon.