Assume that, when we walk, in addition to a fluctuating vertical force, we exert a periodic lateral force of amplitude 25 NN at a frequency of about 1 HzHz. Given that the mass of the bridge is about 2000 kgkg per linear meter, how many people were walking along the 144-mm-long central span of the bridge at one time, when an oscillation amplitude of 75 mmmm was observed in that section of the bridge

Answer:

v = 15.65 m/s

Explanation:

We use conservation of mechanical energy between initial (i) and final (f) states:

Pi + KEi = Pf + KEf

At the top of the cave at the instant the bat starts to fall, there is only potential energy since the bat's velocity is zero.

Pi = m g h = 600 J

and the KEi = 0 J (no velocity)

Knowing the height of the cave's roof (12.8 m) , we can find the mass of the bat:

m = 600 J / (g 12.5) = 4.9 kg

Using conservation of mechanical energy, the final state is:

Pf + KEf = 600 J

with Pf = 0 (just touching the ground)

KEf= 1/2  4.9 (v^2)

and we solve for the velocity:

600 J = 0 + 1/2  4.9 (v^2)

v^2 = 600 * 2 / 4.9 = 244.9

v = 15.65 m/s

Answer:

here u go

Explanation:

Earth's rotation is the rotation of planet Earth around its own axis. Earth rotates eastward, in prograde motion. As viewed from the north pole star Polaris, Earth turns counterclockwise.

Answer:

85.4 N

Explanation:

Weight of the ball, W = 60 N

W = mg, m is mass

m = W/g

m = 60/9.8 = 6.12 kg

Length of a rope, r = 6 m

Speed, v = 5 m/s

We need to find the tension in the rope at this point. Tension is equal to the centripetal force It is given by :

[tex]F=\dfrac{mv^2}{r}+mg\\\\F=\dfrac{6.12\times (5)^2}{6}+60\\\\=85.5\ N[/tex]

So, the correct option is (b) " 85.4 N".

Answer:

Power_input = 85.71 [W]

Explanation:

To be able to solve this problem we must first find the work done. Work is defined as the product of force by distance.

[tex]W = F*d[/tex]

where:

W = work [J] (units of Joules)

F = force [N] (units of Newton)

d = distance [m]

We need to bear in mind that the force can be calculated by multiplying the mass by the gravity acceleration.

Now replacing:

[tex]W = (80*10)*3\\W = 2400 [J][/tex]

Power is defined as the work done over a certain time. In this way by means of the following formula, we can calculate the required power.

[tex]P=\frac{W}{t}[/tex]

where:

P = power [W] (units of watts)

W = work [J]

t = time = 40 [s]

[tex]P = 2400/40\\P = 60 [W][/tex]

The calculated power is the required power. Now as we have the efficiency of the machine, we can calculate the power that is introduced, to be able to do that work.

[tex]Effic=0.7\\Effic=P_{required}/P_{introduced}\\P_{introduced}=60/0.7\\P_{introduced}=85.71[W][/tex]

because of gravitional pull

Answer:

0.78 m

Explanation:

I just did a hw question for this its just 344  divided by 440

Answer:

The force is [tex]F = 0.1441 \ N[/tex]

Explanation:

From the question we are told that

   The volume of blood ejected is  [tex]V_b = 65cm^3 = 65*10^{-6} \ m^3[/tex]

    The velocity of the ejected blood is  [tex]v = 98 cm/ s = 0.98 \ m/s[/tex]

    The mass density of blood is  [tex]\rho = 1060 \ kg/m^3[/tex]

    The heart rate is  [tex]R = 61 bpm(beats \ per \ miunite) = \frac{61}{60} = 1.0667\ bps[/tex]

Generally the average force exerted is mathematically represented as

     [tex]F = 2 * \rho * V_b * R * v[/tex]

=>   [tex]F = 2 * 1060 * (65*10^{-6}) *1.0667 * 0.98[/tex]

=>   [tex]F = 0.1441 \ N[/tex]    

Answer:

it implies our universe is expanding

Answer:

with the increase in mass of the object , the force of gravitation increases that eventually increases the potential energy if the object is still fixed in its relative position with surrounding objects.

Explanation:

hopes this will help you

Answer:

880J/kelvin

Explanation:

Q =MC ×change in t

c =C/m

C=Q/change in t

c= Q/ m× change in t

c = 26400 / 2.0 × 15

c = 880 J/kelvin

Answer:

The force will be "[tex]9.8\times 10^{-3} \ N[/tex]".

Explanation:

The given values are:

Mass,

m = 1 gram

Angle,

Ф = 20°

As we know,

⇒ [tex]F=mg[/tex]

On substituting the given values in the above expression, we get

⇒     [tex]=(1.0\times 10^{-3})(9.8)[/tex]

⇒     [tex]=9.8\times 10^{-3} \ N[/tex]

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:

The value is  [tex]\Delta s = 8.537 *10^{25 } \ J/K[/tex]

Explanation:

From the we are told that

   The radius of the sphere is [tex]r = 6.32 *10^{8} \ m[/tex]

   The temperature is [tex]T_x = 5350 \ K[/tex]

    The average temperature of the rest of the universe is  [tex]T_r = 2.73 \ K[/tex]

Generally the change in entropy of the entire universe per second is mathematically represented as

         [tex]\Delta s = s_r - s_x[/tex]

Here [tex]s_r[/tex] is the entropy of the rest of the universe which is mathematically represented as

          [tex]s_r = \frac{Q}{T_r}[/tex]

Here Q is the quantity of heat radiated by the star which is mathematically represented as

           [tex]Q = 4 \pi * r^2 * \sigma * T^4_x[/tex]

Here [tex]\sigma[/tex] is the Stefan-Boltzmann constant with value  

           [tex]\sigma = 5.67 * 10^{-8 }W\cdot m^{-2} \cdot K^{-4}.[/tex]

=>         [tex]Q = 4 \pi * (6.32*10^{8})^2 * 5.67 * 10^{-8 } * 5350 ^4[/tex]

=>         [tex]Q = 2.332 *10^{26} \ J[/tex]

So

      [tex]s_r = \frac{2.332 *10^{26}}{2.73}[/tex]

=>   [tex]s_r = 8.5415 *10^{25}\ J/K[/tex]

Here [tex]s_x[/tex] is the entropy of the rest of the universe which is mathematically represented as

      [tex]s_x = \frac{Q}{T_x}[/tex]

=>   [tex]s_x = \frac{2.332 *10^{26} }{5350}[/tex]

=>   [tex]s_x = 4.359 *10^{22} \ J/K[/tex]

So

      [tex]\Delta s = 8.5415 *10^{25} - 4.359 *10^{22}[/tex]

=>   [tex]\Delta s = 8.537 *10^{25 } \ J/K[/tex]

This question involves the concepts of entropy and the thermal radiation

The entropy of the entire universe is increased by "8.41 x 10²⁵ J/k

".

The increase in entropy is given as follows:

[tex]\Delta s = s-s_T[/tex]

where,

Δs = increase in entropy = ?

σ = Stefan-Boltzman's constant = 5.67 x 10⁻⁸ W/m².k⁴

A = surface area = 4πr² = 4π(6.32 x 10⁸ m)² = 5.01 x 10¹⁸ m²

Tr = Absolute temperature of the star = 5350 K

T = absolute temperature of the rest of the universe = 2.73 k

Q = thermal radiation energy

Q = [tex]\sigma A T_r^4=(5.67\ x\ ^{-8}\ W/m^2.k^4)(5.01\ x\ ^{18}\ m^2)(5350\ k)^4=2.3\ x\ 10^{26}\ J[/tex]

s = entropy of the universe = [tex]\frac{Q}{T}=\frac{2.3\ x\ 10^{26}\ J}{2.73 k}=8.42\ x\ 10^{25}\ J/k[/tex]

[tex]s_T[/tex] = entropy of the star = [tex]\frac{Q}{T_r}=\frac{2.3\ x\ 10^{26}\ J}{5350\ k}=4.3\ x\ 10^{22}\ J/k[/tex]

Therefore,

Δs = 8.42 x 10²⁵ J/k - 4.3 x 10²² J/k

Δs = 8.41 x 10²⁵ J/k

Learn more about entropy here:

https://brainly.com/question/13146879?referrer=searchResults

Answer:

1.3

Explanation:

sbsbsbsnsnssnssssssiejejeneene

Answer:

it takes him 22.36 seconds to cover that distance

Explanation:

We can solve this problem using the kinematic equation for uniformly accelerated motion:

[tex]x_f-x_i=v_0*t\,+\,\frac{1}{2} a\,*\,t^2[/tex]

which replacing the values given for our case becomes:

[tex]375=0*t\,+\,\frac{1}{2} (1.5)\,t^2\\375=\frac{1}{2} (1.5)\,t^2[/tex]

and which solving for t gives:

[tex]375=\frac{1}{2} (1.5)\,t^2\\t^2=2*375/1.5\\t^2=500\\t=\sqrt{500} \\t \approx 22.36\,\,sec[/tex]

Answer:

Explanation:

The density of a substance is the ratio of its mass to its volume. Its unit of measurement is kg[tex]m^{-3}[/tex].

i.e density, ρ = [tex]\frac{mass}{volume}[/tex]

1a. To determine the density of the acetic acid, Rachael needs to know the mass and volume of the acid.

i. Measure the mass of the given beaker using the mass balance.

ii. Transfer the acetic acid into the beaker, and measure the new mass using the mass balance.

iii. Subtract the mass of the beaker from the new mass to determine the mass of the acetic acid.

iv. Measure the volume of the acid on the scale of the beaker.

v. Divide the value of the mass by its volume to determine its density of the acetic acid.

b. Given that the density is 1.05 g/[tex]cm^{3}[/tex], and volume is 200 [tex]cm^{3}[/tex].

Then,

density = [tex]\frac{mass}{volume}[/tex]

1.05 = [tex]\frac{mass}{200}[/tex]

mass = 1.05 x 200

         = 210 g

mass = 210 g

2. Length of titanium = 0.40 m

   Area of titanium = 0.05 [tex]m^{2}[/tex]

mass = 90.0 kg

density = [tex]\frac{mass}{volume}[/tex]

But,

volume = area x length

            = 0.05 x 0.4

           = 0.02 [tex]m^{3}[/tex]

density of titanium = [tex]\frac{90}{0.02}[/tex]

                = 4500 kg[tex]m^{-3}[/tex]

Answer:

chemical potential of a species is energy that can be absorbed or released due to a change of the particle number of the given species, e.g. in a chemical reaction or phase transition.

Explanation:

The maximum height reached by the squirrel : 0.479 m

Given

vo= 4 m/s

θ = 50 °

Required

The maximum height

Solution

Parabolic motion :

[tex]\tt h_{max}=\dfrac{v_o^2sin^2\theta}{2.g}[/tex]

Input the value

[tex]\tt h_{max}=\dfrac{4^2\times (sin~50)^2}{2\times 9.8}\\\\h_{max}=0.479~m[/tex]

or you can use

Find t from vt= vo sin θ - gt(negative sign=against gravity)⇒vt=0 at peak(the maximum height)

and input t to vertical component : y=voy.t-1/2gt²

Answer:

this is a homework helping website I don't know If I can help you with this problwm

Answer:

Electrical to Thermal

Answer;

2.6

Explanation;

Answer:

C

Explanation:

covalent. Hope that helps!

Answer:

i think it's d

Explanation:

Answer:

D

Explanation:

i feel like this one is it

Answer:

The apparent fit of the eastern coastline of South America and western coastline of Africa

Similarities of plants and animal fossils in South America and some parts of African continent which were separated by a vast ocean

Similarities in the sequence of rock layers of opposite sides of the Atlantic Ocean

Answer:

Force

Explanation:

Only a force can cause a stationary object to move or a moving object to change its speed or direction.

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

force between the two charges (+q1 and +q2),if they are at a distance 'a' is

F1=1/4pieEo q1q2/d^2................ (1)

when the metal spheres are in contact the charge flow from one sphere to another till both the sides acquires the same charge. here q1 and q2 are of same sign,hence after contact each sphere will have a charge

[tex] \binom{q1 + q2 }{2} [/tex]

now,the force between them,

f2=1/4pieEo

(q1+q2/2)^2/d^2

from eq (1)and eq (2)

f2=f1 (q1+q2)^2/4q1q2