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2 years ago

A small car with mass of 0.800 kg travels at a constant speed

Physics

1 answer:

Alexandra [31]2 years ago

7 0

Answer:

The equation of equilibrium at the top of the vertical circle is:

\Sigma F = - N - m\cdot g = - m \cdot \frac{v^{2}}{R}

The speed experimented by the car is:

\frac{N}{m}+g=\frac{v^{2}}{R}

v = \sqrt{R\cdot (\frac{N}{m}+g) }

v = \sqrt{(5\,m)\cdot (\frac{6\,N}{0.8\,kg} +9.807\,\frac{kg}{m^{2}} )}

v\approx 9.302\,\frac{m}{s}

The equation of equilibrium at the bottom of the vertical circle is:

\Sigma F = N - m\cdot g = m \cdot \frac{v^{2}}{R}

The normal force on the car when it is at the bottom of the track is:

N=m\cdot (\frac{v^{2}}{R}+g )

N = (0.8\,kg)\cdot \left(\frac{(9.302\,\frac{m}{s} )^{2}}{5\,m}+ 9.807\,\frac{m}{s^{2}} \right)

N=21.690\,N

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A 60kg bicyclist (including the bicycle) is pedaling to the

Fittoniya [83]

a) 4 forces

b) 186 N

c) 246 N

Explanation:

Let's count the forces acting on the bicylist:

1) Weight ( $W=mg$ ): this is the gravitational force exerted on the bicyclist by the Earth, which pulls the bicyclist towards the Earth's centre; so, this force acts downward (m = mass of the bicyclist, g = acceleration due to gravity)

2) Normal reaction (N): this is the reaction force exerted by the road on the bicyclist. This force acts vertically upward, and it balances the weight, so its magnitude is equal to the weight of the bicyclist, and its direction is opposite

3) Applied force ( $F_A$ ): this is the force exerted by the bicylicist to push the bike forward. Its direction is forward

4) Air drag ( $R$ ): this is the force exerted by the air on the bicyclist and resisting the motion of the bike; its direction is opposite to the motion of the bike, so it is in the backward direction

So, we have 4 forces in total.

Here we can find the net force on the bicyclist by using Newton's second law of motion, which states that the net force acting on a body is equal to the product between the mass of the body and its acceleration:

$F_{net}=ma$

where

$F_{net}$ is the net force

m is the mass of the body

a is its acceleration

In this problem we have:

m = 60 kg is the mass of the bicyclist

$a=3.1 m/s^2$ is its acceleration

Substituting, we find the net force on the bicyclist:

$F_{net}=(60)(3.1)=186 N$

We can write the net force acting on the bicyclist in the horizontal direction as the resultant of the two forces acting along this direction, so:

$F_{net}=F_a-R$

where:

$F_{net}$ is the net force

$F_a$ is the applied force (forward)

$R$ is the air drag (backward)

In this problem we have:

$F_{net}=186 N$ is the net force (found in part b)

$R=60 N$ is the magnitude of the air drag

Solving for $F_a$ , we find the force produced by the bicyclist while pedaling:

$F_a=F_{net}+R=186+60=246 N$

3 0

3 years ago

What mass of water must evaporate from the skin of a 70.0 kg man to cool his body 1.00 ∘C? The heat of vaporization of water at

romanna [79]

Answer:

100 cc

Explanation:

Heat released in cooling human body by t degree

= mass of the body x specific heat of the body x t

Substituting the data given

Heat released by the body

= 70 x 3480 x 1

= 243600 J

Mass of water to be evaporated

= 243600 / latent heat of vaporization of water

= 243600 / 2420000

= .1 kg

= 100 g

volume of water

= mass / density

= 100 / 1

100 cc

1 / 10 litres.

6 0

3 years ago

Compare the planets Mars and Saturn. Describe how their common characteristics are similar and Compare the planets Earth and Nep

nordsb [41]

Question no. 1. Compare the planets Mars and Saturn. Describe how their common characteristics are similar:

Answer: Our solar system is located in the outer spiral arm of the milky way galaxy. our solar system has one sun and nine revolving planets and . namely

Mercury
Venus
Earth
Mars
Jupiter
Saturn
Uranus
Neptune
Pluto (small planet usually refer as dwarf)

Each star has its on moon/moons and has its own characteristics i.e , planet must be a celestial body , must have orbit around sun, have enough mass for self gravity, big enough to have gravity that clear its path from other same size object close to its orbit around sun.

Mars is the fourth from the sun and sixth is the Saturn from the sun in our solar system.

Common in Characteristics of Mars and Saturn:

Mars and Saturn both have celestial body.
Mars and Saturn both have enough mass for the gravity to get rid of rigid body forces.
Mars and Saturn both revolve around the sun in their own orbits.
Mars is the second smallest in the solar system while Saturn is second largest in the solar system.
Mars and Saturn both have their own moons. Mars has two while Saturn has 83 moons
Mars and Neptune both do not support life.

Question no. 2. Compare the planets Earth and Neptune. Describe how are they different from each other

Answer:

Earth our home planet is the third from the sun and Neptune on the other hand is the eighth from the sun in the solar system.

Common differences between Earth and Neptune

Earth is the terrestrial planet while Neptune (Ice giant) is the Jovian planet.
Earth has no ring around it, Neptune has ring around it.
Earth is closer to the sun and Neptune is far distant from the sun.
Earth consists of rocks and metals on the other hand Neptune contain gases
Earth is smaller than the Neptune in the solar system.
Earth rotates slower and Neptune rotates faster.

4 0

3 years ago

Which best describes the current atomic model?

Lorico [155]

A: It is not an exact representation of the atom, but is close enough to be very useful.

Hope this helps!

3 0

3 years ago

Read 2 more answers

A 500 W hair dyer is used to dry hair for 6 minutes a day for 3 days. How much energy is used? A laptop uses 75 W. The cot of el

zzz [600]

Answer:

See the answers below.

Explanation:

We will solve this problem by calculating each part separately.

A 500 W hair dyer is used to dry hair for 6 minutes a day for 3 days.

Energy can be calculated by multiplying the value of the power of the equipment by the amount of time of use.

$500 [W]*[\frac{6min}{1day} ]*[\frac{1day}{24hr} ]*[\frac{1hr}{60min} ]=2.083 [W]$

The cots of electricity is 5.6 cents per kWh. How much would it cost to operate the laptop for 24 hours a day for one week?

We know that the power of the latop is 75 [W], then we can calculate the cost, multiplying the value of the power by the value of the cost by the time of use of the computer.

$0.075[kW]*5.6[\frac{cents}{kw*h}}]*[\frac{24hr}{1day}]*[1week]*[\frac{7days}{1week} ]=70.56 [cents]$

A toaster oven is 85% efficient. It uses 1200 J of energy. How much thermal energy is it producing?

Efficiency is defined as the relationship between the energy obtained on the energy delivered. Almost always the energy delivered is greater than the energy obtained (first law of thermodynamics).

Therefore.

$Effic = E_{obtained}/E_{delivered}\\0.85=E_{obtained}/1200\\E_{obtained}=1020[J]$

4 0

2 years ago