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-Dominant- [34]
4 years ago
9

B. A car moving at an initial speed vi applies its brakes and skids for some distance until coming to a complete stop. If the co

efficient of kinetic friction between tires and the road is µk what distance did the car skid?

Physics
1 answer:
wariber [46]4 years ago
3 0

Complete Question

The complete question is  shown on the first uploaded image  

Answer:

The distance which the car skid is  l  =  \frac{v_i^2 }{2 *  \mu_k  * g }

Explanation:

From the question we are told that  

     The  initial velocity of the car is  v_i

     The  coefficient of kinetic friction is  \mu_k

According to the law of energy conservation

    The initial Mechanical Energy =  The final  Mechanical Energy  

                           M_i  = M_f  

The initial mechanical energy is  mathematically represented as  

              M_i  =  KE _o  + PE_e

where KE is the initial kinetic energy which is  mathematically represented as

        KE  =  \frac{1}{2} m v_i^2

And  PE  is  the initial potential energy which is  zero given that the car is  on the ground

     Now  

           M_f =  W_{\mu}

Where  W_{\mu} is  the work which friction exerted on the car  which is  mathematically represented as

       W_{\mu} =  m*  \mu_k  *  g  *  l

Where  l is the distance covered by the car before it slowed down

        \frac{1}{2} m v_i^2  = m*  \mu_k  *  g * l

=>     l  =  \frac{v_i^2 }{2 *  \mu_k  * g }

                 

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Answer:

Explanation:

mass of refrigerator, m = 110 kg

coefficient of static friction, μs = 0.85

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F = 916.3 N

(b) The force required to move the refrigerator with constant speed

F' = μk x mg

F' = 0.59 x 110 x 9.8

F' = 636.02 N

(c) Let a be the acceleration.

Net force = Applied force - friction force

F net = 950 - 636.02

F net = 313.98 N

a = F net / mass

a = 313.98 / 110

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4 0
3 years ago
Can someone help me with the 10th one which is circled
PtichkaEL [24]
Force can be exerted into an object with out it moving, but if you were to move the object due to force it would be considered work. (yes, you can exert force without having the object moving)
6 0
3 years ago
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A fire engine is moving south at 35 m/s while blowing its siren at a frequency of 400 Hz.
vodomira [7]

To solve this problem we will apply the concepts related to the Doppler effect. The Doppler effect is the change in the perceived frequency of any wave movement when the emitter, or focus of waves, and the receiver, or observer, move relative to each other. Mathematically it can be described as

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Here,

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f_s=frequency of wave emitted by source

v_d=velocity of detector

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Replacing we have that,

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4 years ago
Calculate the radius of the orbit of a proton moving at 2.2x10^6 m/s in a magnetic field 0.7 T where v and B are perpendicular.
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Answer:

3.28 cm

Explanation:

To solve this problem, you need to know that a magnetic field B perpendicular to the movement of a proton that moves at a velocity v will cause a Force F experimented by the particle that is orthogonal to both the velocity and the magnetic Field. When a particle experiments a Force orthogonal to its velocity, the path it will follow will be circular. The radius of said circle can be calculated using the expression:

r = \frac{mv}{qB}

Where m is the mass of the particle, v is its velocity, q is its charge and B is the magnitude of the magnetic field.

The mass and  charge of a proton are:

m = 1.67 * 10^-27 kg

q = 1.6 * 10^-19 C

So, we get that the radius r will be:

r =  \frac{1.67 * 10^-27 kg * 2.2*10^6 m/s}{1.6 * 10^-19 C* 0.7 T} = 0.0328 m, or 3.28  cm.

8 0
3 years ago
When two or more capacitors are connected in series across a potential difference:
34kurt

Answer:

A) and B) are correct.

Explanation:

Let's take a look at the attached picture. Now

The total voltage across both capacitors is the same as the sum of the voltage from each device, that statement is true for any electrical device connected in series. So a) is TRUE

The equivalent capacitance is going to be: \frac{1}{C_{total}}=\frac{1}{C_1} +\frac{1}{C_2}

And that value can be mathematically proven that is always less than any of the values of each capacitor. So b is TRUE

And through both capacitors flow the same current, but the amount of charge depends on the value of the capacitors, so only could be the same if the capacitors are the same value. Otherwise, don't. C) not always, so FALSE

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3 years ago
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