A 87 kg man has a total mechanical energy of 1780 J .If he is swinging downward and is currently 1.4 m above the ground, what is his speed? Use g = 10 m/s^2

Answer:

[tex] \underline{ \boxed{ yes}}\\[/tex]

Explanation:

[tex]given : initial \: velocity \: (u )= 40 {ms}^{ - 1} \\ given : final \: velocity \: (u )= 0 {ms}^{ - 1} \\ given : - (acceleration) \: (a_r) = 2 {ms}^{ - 2} \\ given : distance \: (s) \: = \: ? : \\ but \: {v}^{2} = {u}^{2} + 2( a)s\\ {0}^{2} = {40}^{2} + 2( - 2)s \\ - {40}^{2} = - 4s \\ s = \frac{ - {40}^{2} }{ - 4} \\ s = \frac{1600}{4} \\s = 400 \: m[/tex]

Answer:

Second and Last Option Are Correct

Explanation:

Answer:

D is the answer  I think (0 w 0 )

Explanation:

The  glaciers move gradually. Hence, option (C) is correct.

A glacier is a long-lasting mass of heavy ice that is perpetually moving. When the ablation of snow is greater than the accumulation over a long period of time, frequently centuries, a glacier forms.

As it slowly flows and deforms under forces brought on by its weight, it gains distinctive features like crevasses and seracs. Cirques, moraines, and fjords are the result of the erosion of rock and debris from its substrate as it travels.

The considerably thinner sea ice and lake ice that form on the surface of bodies of water are not the same as glaciers, which form only on land and may flow into water bodies.

The huge ice sheets, commonly referred to as "continental glaciers," in the polar areas of the planet contain 99 percent of the planet's glacial ice.

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Answer:

Explanation:

These tectonic plates rest upon the convecting mantle, which causes them to move. The movements of these plates can account for noticeable geologic events such as earthquakes, volcanic eruptions, and more subtle yet sublime events, like the building of mountains.

Answer:

Tectonic plates recurring over and over again cause a rupture in the Earth's crust. This agitates the magma in volcanoes, causing the volcano to erupt.

Explanation:

Answer:

TRUE

Explanation:

IM SMART

Answer:

Stay  Safe! ,God bless you . The answer is false ,

Explanation:

Answer:

a)   d = 12 km, d = 0,  b)  v = 0.4 km / min, v = 0,  c) v = 0

Explanation:

This problem asks to find the distance and the displacement. We must emphasize that the distance is a scalar and the displacement is a vector quantity

In the exercise, the bold letters indicate vectors

a) Let's find the total distance of the trip

           d = d₁ + d₂

where d₁ is the distance to get to the flowers and d₂ is the distance to return to the hive from the flowers

             d₁ = d₂ = 6 km

             d = 12 km

we look for the displacement that is a vector quantity

          d = d₁ - d₂

since the second displacement is in the opposite direction of the first

          d = 0

b) the average speed of the trip, again this magnitude is a scalar

          v = d / t

distance is d = 12 km t total time is t = 15 + 15 = 30 min

          v = 12/30

          v = 0.4 km / min

average velocity (vector) of the entire travel, in that case the displacement is zero

          v = 0

c) If the path is not a straight line but the time is the same, the average speed cannot be calculated since it lacks the distance value

In the same case to calculate the average velocity that is a vector, it will be zero since the net displacement is zero

            v = 0

Answer:

conduction I believe if not its convection

Answer: Conduction transfers energy from the spoon to the hot chocolate.

Explanation: Heated water molecules and steam rise in the beaker, carrying heat by convection.

Answer:

6.79 m/s

Explanation:

By applying the principle of conservation of momentum.

The total momentum = MV - mv = 0 (since the squid is beginning at rest)

the mass of the squid (M) in absence of water in its cavity = (6.5 - 1.75) kg

= 4.75 kg

speed of the squid (V) = 2.5 m/s

mass of the water expelled (m) = 1.75 kg

speed of the water (v) = ???

∴

4.75 × 2.5 = 1.75 × v

[tex]v = \dfrac{4.75 \times 2.5}{1.75 }[/tex]

v = 6.79 m/s

Answer:

8.34 x 10⁻⁶N

Explanation:

Given parameters:

Mass 1  = 100kg

Mass 2 = 200kg

Distance of separation  = 40cm = 0.4m

Unknown:

Gravitational force of attraction between them  = ?

Solution:

To solve this problem, we use the expression below which is derived from the Newton's law of universal gravitation:

           Fg  = [tex]\frac{G x mass 1 x mass 2}{d^{2} }[/tex]

G is the universal gravitation constant = 6.67 x 10⁻¹¹

d is the separation

 Now;

  Fg = [tex]\frac{6.67 x 10^{-11} x 100 x 200}{0.4^{2} }[/tex]   = 8.34 x 10⁻⁶N

Answer:

Which element?

U did not mention it

Answer:

[tex]9\:\mathrm{J}[/tex]

Explanation:

Kinetic energy is given by the following equation:

[tex]KE=\frac{1}{2}mv^2[/tex], where [tex]m[/tex] is mass in [tex]\mathrm{kg}[/tex] and [tex]v[/tex] is velocity in [tex]\mathrm{m/s}[/tex].

Since the cell phone's mass is given in grams, we need to convert this into kilograms:

[tex]80\:\mathrm{g}\cdot \frac{1\:\mathrm{kg}}{1000\:\mathrm{g}}=0.08\:\mathrm{kg}[/tex].

Therefore, the kinetic energy of the cell phone is:

[tex]KE=\frac{1}{2}\cdot 0.08\cdot 15^2=\fbox{$9\:\mathrm{J}$}[/tex].

Answer:

45.9m

Explanation:

Given parameters:

Mass of roller coaster train  = 12000kg

Velocity  = 30m/s

Unknown:

Tallest hill the roller coaster train can reach = ?

Solution:

Kinetic energy is the energy due to the motion of body.

Potential energy is the energy due to the position of a body.

So;

             [tex]\frac{1}{2}[/tex]  m v²    =  mgh  

 m is the mass, g is the acceleration due to gravity, h is the height and v is the velocity

                 m v²   = 2mgh

                     v²   = 2gh

                   h  = [tex]\frac{v^{2} }{2g}[/tex]  

                  h  = [tex]\frac{30^{2} }{2 x 9.8}[/tex]   = 45.9m  

Answer:

They both have an equal temperature.

Explanation:

Any material or object that allow the conduction (transfer) of electric charge or thermal energy is generally referred to as a conductor. Some examples of a conductor are metals, copper, aluminum, graphite, etc.

In the process of heat conduction, thermal energy is usually transferred from fast moving particles to slow moving particles during the collision of these particles. Also, thermal energy is typically transferred between objects that has different degrees of temperature and materials (particles) that are directly in contact with each other but differ in their ability to accept or give up electrons.

Hence, if two objects have different temperatures when they come in contact, heat will flow from the warmer object to the cooler one until they both have an equal temperature.

Answer:

15 seconds

Explanation:

If car was moving at 20m/s for 3 sec.

if car traveled 100m = 15 sec total

Answer:

Noah caught 35 Noah on Satuday.

Explanation:

Given that,

Kieran caught 53 Pokemon

Kieran caught 18 more Pokémon on Saturday than  Noah did.

Let Noah caught x Pokémon on Saturday.

ATQ,

18 + x = 53

Thie is the equation that can be used to find the value of x.

Subtract 18 from both sides.

18 + x -18 = 53 - 18

x = 35

Hence, Noah caught 35 Noah on Satuday.

Answer:

C. A heat engine must deposit some energy in a cold reservoir.

Explanation:

The second law of thermodynamics says that "It is impossible to extract an amount of heat Q from a hot reservoir and use it all to do work W. Some amount of heat q must be exhausted to a cold reservoir."

This means that if we extract an amount of heat Q from the hot reservoir, the work W can never be exactly equal to Q, then there is a surplus of heat q that must be deposited in a cold reservoir.

Then we have the equation:

Q = W + q

From this we can conclude that the correct option is:

C. A heat engine must deposit some energy in a cold reservoir.

There will be always some energy that is not transformed into work, and is deposited in a cold reservoir.

C. A heat engine must deposit some energy in a cold reservoir.

Therefore, option C is correct.

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Answer:

Density of Air = ([tex]P_{1}[/tex]  - [tex]P_{2}[/tex] )/(g x h)

Density of Air =  1.27 Kg/[tex]m^{3}[/tex]

Explanation:

Note: This question is not complete, and lacks its first part in which it contains important data to solve for the density of air. But, I have found the similar question and its data. So. I will be solving the question for the sack of understanding and concept.

Missing part: A weather balloon has an absolute-pressure sensor attached. On the ground the sensor reads [tex]P_{1}[/tex]  = 1.01x [tex]10^{5}[/tex] Pa. At a height of h = 950 m, the sensor reads [tex]P_{2}[/tex]=8.92x[tex]10^{4}[/tex] Pa.

Solution:

Let

[tex]P_{1}[/tex] be the pressure of the balloon at ground.

[tex]P_{2}[/tex] be the pressure of the balloon at height h = 950 m

g = acceleration due to gravity,

In order to derive the expression, we need to find the pressure difference:

Pressure difference = ΔP

ΔP = [tex]P_{1}[/tex]  - [tex]P_{2}[/tex]

As we know that,

Pressure difference = density x acceleration due to gravity x height.

So,

ΔP = [tex]P_{1}[/tex]  - [tex]P_{2}[/tex]  = (Density of Air) x (g) x (h)

We need expression for the density of air, so,

Density of Air = ΔP / (g x h)

Hence, the expression is:

Density of Air = ([tex]P_{1}[/tex]  - [tex]P_{2}[/tex] )/(g x h)

Now, we can calculate the density of air as well, by putting the values given above in the data.

[tex]P_{1}[/tex]  =  1.01 x [tex]10^{5}[/tex]

[tex]P_{2}[/tex] = 8.92 x [tex]10^{4}[/tex]

g = 9.8 m/s

h = 950 m

So,

Density of Air = ((1.01 x [tex]10^{5}[/tex]) - (8.92 x [tex]10^{4}[/tex]) )/ (9.8 x 950)

Density of Air =  1.27 Kg/[tex]m^{3}[/tex]

An expression for an estimate of the density of air is; ρ = ( P₁ - P₂)/gh

According to pascal's principle;

ΔP = ρgh

Where;

ΔP is change in pressure = P₁ - P₂

g is acceleration due to gravity

h is height of pressure change

Now, we want to find an expression for an estimate of the density of air. This means we want to make density the subject of the formula. Thus;

ΔP = ρgh

⇒ divide both sides by gh to get;

ρ = ΔP/(gh)

Recall that ΔP = P₁ - P₂

Thus; ρ = ( P₁ - P₂)/gh

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Answer:

A)5524J,

B) 29.2Nm

Explanation:

This question can be treated using work- energy theorem

Work= change in Kinectic energy

W= Δ KE

Work= difference between the final Kinectic energy and intial Kinectic energy.

We know that

Kinectic energy= 1/2 mv^2 .............eqn(1)

This can be written in term of angular velocity, as

KE= 1/2 I

The sound wave does not damage the air because no external factors such as reflection, amplification, and vibrations are present. However, in the launch pad factors such as reflection, amplification, and vibrations are present which damages the sound wave.  

Closeness to the Sound Source: When a rocket is fired on the launchpad, it creates a tremendous amount of noise in proximity to the nearby equipment and structures.

When a rocket is launched, concentrated sound waves are created that can seriously harm neighboring structures, especially if such structures are not built to handle such strong vibrations. In contrast, once a rocket is in the air, the sound waves spread out and become less forceful as they travel through the atmosphere, decreasing the possibility that they may cause harm.

Reflection and Amplification: The launchpad environment can serve as an echo chamber for sound waves because of its huge, solid structures.

Hence, The sound wave does not damage the air because no external factors such as reflection, amplification, and vibrations are present. However, in the launch pad factors such as reflection, amplification, and vibrations are present which damages the sound wave.  

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Answer:

reducing temperature of the surrounding

Explanation:

combustion reactions are exothermic so they give off heat. reducing the temperature of the surrounding will enable more efficient energy transfer

Answer:

12.31 m/s

Explanation:

If we recall from the previous knowledge we had about speed,

we will know that:

speed = distance/ time.

As such:

The average speed of the rider bicycle is

average speed = total distance/ total time

Mathematically, it can be computed as:

[tex]v_{avg} = \dfrac{d+d}{\dfrac{d}{v_1}+ \dfrac{d}{v_2}}[/tex]

[tex]v_{avg} = \dfrac{2d}{\dfrac{d}{10 \ m/s}+ \dfrac{d}{16 \ m/s}}[/tex]

[tex]v_{avg} = \dfrac{2}{\dfrac{1}{10 \ m/s}+ \dfrac{1}{16 \ m/s}}[/tex]

[tex]v_{avg} = \dfrac{2}{\dfrac{13}{80 \ m/s}}[/tex]

[tex]\mathbf{v_{avg} =12.31 \ m/s}[/tex]

Answer:

[tex]v_f=2\:\mathrm{m/s}[/tex]

Explanation:

From the Law of Conservation of Momentum, momentum is conserved. Therefore, we can set up the following equation:

[tex]m_1v_1+m_2v_1=m_fv_f[/tex]

Since the 5kg toy car was initially and rest, [tex]m_2v_2=0[/tex].

Therefore, plugging in our values, we have:

[tex]10\cdot 3=(10+5)v_f,\\v_f=\frac{30}{15},\\v_f=\fbox{$2\:\mathrm{m/s}$}[/tex].

Answer:

Let m1 = mass of big toy car=10kg

m2= mass of small toy car= 5kg

U1= initial velocity of big toy car= 3m/s

U2= initial velocity of small toy car=0

Since the big toy car moved the small one after the collision, their final velocity will be the same.

m1u1 + m2u2= (m1+m2)v

10(3)+(5)(0)=(10+5)v

30=15v

Divide both sides by 15

V=2

The final velocity is 2m/s

Explanation:

Answer:

0.25 kg

Explanation:

p = mv

2 = m(8)

2/8 = m(8)/8 *cancels

m = 1/4 OR 0.25 kg

Answer:

C. The sum remains the same.

Explanation:

The sum of the kinetic and potential energy remains the same as the all rolls from point A to E.

We know this based on the law of conservation of energy that is in play within the system.

The law of conservation of energy states that "energy is neither created nor destroyed within a system but transformed from one form to another".