pls help me do these physic questions

If the spring constant is known, the extension or compression of the spring can be used to calculate the applied force (pull or push) on the spring.

According to Hook's law, the force applied to an elastic material is directly proportional to the extension of the material.

The force applied;

F = kx

where;

The applied force can be in form of push or pull. A push force can result in compression of the spring while a pull force can result in extension of the spring.

If the spring constant is known, the extension or compression of the spring can be used to calculate the applied force (pull or push) on the spring.

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Answer:

Explanation:

Givens

m = 15000 kg

t = 12.1 seconds

vi = 86 km / hr

vf =0

Formula

F = m*a

a = (vf - vi)/ t

vi has to be converted to m/s

86 km/hr [1000 m / 1 km] * [1 hour / 3600 seconds]

86 * 1000 / 3600 = 23.89 m/s

Solution

a = (vf - vi) / t

a = (0 - 23.89)/12.1

a = - 1.97 m/s^2 The minus means that the trains is slowing down.

F = 15000 kg * - 1.97 m/s^2

F = -29615.7 Newtons.

Answer:it equals 0

Explanation:hope this is a good answer

Angular velocity is the ratio of angular displacement to time. Then the number of turns by the shaft is zero.

The rate of change of angular displacement is called angular velocity. It is a vector quantity.

We know that the angular velocity formula

[tex]\rm Angular \ velocity = \dfrac{Angular \ displacement}{time}[/tex]

The motor shaft turns through between the time when the current is reversed and the instant when the angular velocity is zero.

Then the number of turns will be

[tex]\rm Number \ of\ turns = Angular \ velocty \times time \\\\Number \ of\ turns = 0 *time \\\\Number \ of\ turns = 0[/tex]

The number of turns by the shaft is zero.

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Geometric optics allows you to find which the correct answer about which false statement is:

  B)  All rays of light refracted by the lens pass through the principal focus.

Geometric optics studies the formation of images using the light geometric properties of optical systems, the main expression for this is:

      [tex]\frac{1}{f} = \frac{1}{p} + \frac{1}{q}[/tex]  

Where f is the focal length, p and q the distance to the object and the image respectively.

There are some points of special interest:

Let's analyze the claims.

A) True. A parallel ray comes from infinity and the image is formed at the focal point.

B) False. The image point is given by the expression above and depends on the distance to the object.

C) True. This is the definition of focal length.

D) True. All distances are measured from the main axis.

In conclusion, using geometric optics we can find that the correct answer about which false statement  is:  

      B)  All rays of light refracted by the lens pass through the principal focus.

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Using the Hubble law v = H₀d where v = recessional speed = 70,000 km per second H₀ = hubble constant = 70 km/s/Mpc and d = distance of galaxy.

Making d subject of the formula, we have

d = v/H₀

Substituting the values of the variables into the equation, we have

d = v/H₀

d = 70000 km/s/70 km/s/Mpc

d = 1000 Mpc

So, the galaxy is 1000 Mpc away from us.

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Answer:

physical science

Explanation:

i guess??

Explanation:

Shorter wavelength since UV light has more energy than visible light

365 nm - What is the peak energy wavelength of UV light?  It allows both infrared daylight and ultraviolet night-time communications by being transparent between 320 nm and 400 nm and also the longer infrared and just-barely-visible red wavelengths. Its maximum UV transmission is at 365 nm

Answer: beta particles

Explanation:

that's the answer

Answer:

[tex]4 ms^{-2}[/tex]

Explanation:

Normal force - should be the reaction from the surface it's on - nullifies the weight of the object. At this point the only force is of [tex]22-14 = 8N[/tex] from whoever is pushing the square and the friction, towards the right. At this point we divide the force by the mass of the object to obtain an acceleration of [tex]8/2 = 4 ms^{-2}[/tex]

Answer: friction :)

Explanation:

I took the test and got 100%

Answer:

stored Energy = Power x time = 65 x 25x 60 = 105.6 Kjoules

Answer:

this is an example of Newton's Second Law, acceleration happens when a force acts on a mass.

the force that makes the bicycle move is your foot pushing against the pedal

Hi there!

We can use the following:

U (Gravitational Potential Energy) = mgh

m = mass of object (kg)

g = acceleration due to gravity OR gravitational field strength

h = height, or displacement (m)

ΔU = Uf - Ui, so:

Uf = 3 × 1.5 × 10 = 45 J

Ui = 3 × 0 × 10 = 0

ΔU = Uf - Ui = 45 - 0 = 45 J

Answer:

a)object is in uniform motion

Explanation:

velocity is constant.and a=0

body is in uniform motion.

BRAINLIST PLS

Explanation:

gravitational potential energy at the top of the hill, which transforms into kinetic energy as he moves bottom of the hill

that's mean potential energy transfoms into kinetic energy

His potential energy is converted into kinetic energy when his speed increases as he goes downhill.

Mechanical energy is the combination of all the energy in motion represented by total kinetic energy and the total potential energy stored energy in the system which is represented by total potential energy.

Total mechanical energy is s the sum of all the kinetic as well as potential energy stored in the system.

ME = KE + PE

When Andrew skis down a hill then he had stored potential energy due to the height of the hill and his gravitational weight,

Due to the height of the slope and his weight, Andrew had potential energy stored when he skied down it.

As he descended the hill, his speed increased, transforming this potential energy into kinetic energy.

Learn more about mechanical energy from here,

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Answer:

D

Unbalanced or net forces acting on the car will cause it to move

The correct answer is option D. The net force on the car is zero​.

Since the car is not accelerating, the force of air resistance and the friction force must add to give the exact opposite of the applied force. The net force here would be zero, as well.

Newton's First Law is the law of inertia. An object with no net forces acting on it which is initially at rest will remain at rest. If it is moving, it will continue to move in a straight line with constant velocity.

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Answer:

the direction of motion of the pulse

Explanation:

u=0, v=?, a=5m/s², t=8sec

So, by the formula,

v=u+at

v=0+5×8

v=40m/s.

hope this helps you .

Answer:

Choice C: Approximately [tex]1.64[/tex].

(Assuming that light entered into this glass block from air.)  

Explanation:

Let [tex]n_{1}[/tex] denote the refractive index of the first medium (in this example, air.) Let [tex]\theta_{1}[/tex] denote the angle of incidence.

Let [tex]n_{2}[/tex] denote the refractive index of the second medium (in this example, the glass block.) Let [tex]\theta_{2}[/tex] denote the angle of refraction.

By Snell's Law:

[tex]n_{1} \, \sin(\theta_{1}) = n_{2}\, \sin(\theta_{2})[/tex].

Rearrange the equation to find an expression for [tex]n_{2}[/tex], the refractive index of the second medium (the glass block.)

[tex]\begin{aligned}n_{2} = \left(\frac{\sin(\theta_{1})}{\sin(\theta_{2})}\right)\, n_{1}\end{aligned}[/tex].

The refractive index of air is approximately [tex]1.00[/tex]. Substitute in the values and solve for [tex]n_{2}[/tex], the refractive index of the glass block:

[tex]\begin{aligned}n_{2} &= \left(\frac{\sin(\theta_{1})}{\sin(\theta_{2})}\right)\, n_{1} \\ &= \left(\frac{\sin(46^{\circ})}{\sin(26^{\circ})}\right)\times 1.00 \\ &\approx 1.64\end{aligned}[/tex].

Answer:

Ink

mud

hcl

ocean water

co2

h20

Answer:

Explanation:

The kinetic energy of an object can be found by using the formula

[tex]k = \frac{1}{2} m {v}^{2} \\ [/tex]

m is the mass in kg

v is the velocity in m/s

From the question

m = 20 kg

v = 2.5 m/s

From the question we have

[tex]k = \frac{1}{2} \times 20 \times {2.5}^{2} \\ = 10 \times 6.25 \\ = 62.5\: \: \: \: \: \: \: \: \: \: [/tex]

We have the final answer as

Hope this helps you

Answer:

a balance and a beaker of water

Explanation:

The mass can easily be measured with balance. If you drop the key in a beaker of water, the water inside the beaker will increase and this increases the volume of water that will be equal to volume of key.

Answer:

It should be mentioned that an efficient way to work this vector addition problem is with the cosine law for general triangles (and since  

a

,

b

 and  

r

 from an isosecles triangle, the angles are easy to figure). However, in the interest of reinforcing the usual systematic approach to vector addition, we note that the angle  

b

 makes with the +x axis  is 30

0

+105

0

=135

0

(a) The x component of  

r

x

​

​

=(10.0m)cos30

0

+(10.0m)cos135

0

=1.59m

(b)  the y component of  

r

 is r

y

​

=(10.0m)sin135

0

 = 12.1 m.

(c) the magnitude of  

r

 is r =  ∣

r

∣=

(1.59m)

2

+(12.1m)

2

​

=12.2m

(d) The angle between  

r

 and the +x direction is tan

−1

[(12.1m)/(1.59m)]=82.5

0

Explanation:

Answer:

Pushing a car and a truck

Explanation:

Answer:

Earth because of greater gravity

Answer:

whats the question

Explanation:

Please find attached photograph for your answer.

Hope it helps.

Do comment if you have any query.

Answer:

Od- Wooden

Explanation:

It would not make sense if it was non-wood because that make it no a wood base product, OC is not right because its not a a plant that produces wood as its structural tissue and thus has a hard stem.   An OA justT o take or get a supply of wood. so its Od

39°C=1.28L

8°C=? Less

=8°C/39°C×1.28L

=8/39×1.28L

=10.24/39

=512/195

=2.6L