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Maslowich
3 years ago
15

On a drive from one city to? another, victor averaged 39 mph. if he had been able to average 72 ?mph, he would have reached his

destination 11 hrs earlier. what is the driving distance between one city and the? other?
Physics
1 answer:
PilotLPTM [1.2K]3 years ago
5 0
Let the unknown distance be xmiles
x/39-x/72=11hr
72x-39x/2808=11hr
33x/2808=11
33x= 30888
x=936miles
U can substitue back to check
at speed of 72mph, he would need 936/72=13hrs
at speed of 39mph, he would need 936/39=24hr
the difference is 24-13=11
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Answer:

d= 1650 km.

Explanation:

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       t = \frac{\Delta x}{v} =\frac{1.9m}{346m/s} = 5.5 msec  (1)

  • The electromagnetic waves travel in free space at the same speed of light in vacuum ( since light is a electromagnetic wave indeed), i.e., 3*10⁸ m/s.
  • Applying the same formula than in (1) we can solve for the distance d, as follows:

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3 years ago
Positive Charge is distributed along the entire x axis with a uniform density 12 nC/m. A proton is placed at a position of 1.00
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Answer:

b.  \Delta KE = 390 eV

Explanation:

As we know that the electric field due to infinite line charge is given as

E =\frac{\lambda}{2\pi \epsilon_0 r}

here we can find potential difference between two points using the relation

\Delta V = \int E.dr

now we have

\Delta V = \int(\frac{\lambda}{2\pi \epsilon_0 r}).dr

now we have

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now plug in all values in it

\Delta V = \frac{12\times 10^{-9}}{2\pi \epsilon_0}ln(\frac{1+5}{1})

\Delta V = 216ln6 = 387 V

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\Delta KE = (e)(387V) = 387 eV

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5.00-kg particle starts from the origin at time zero. Its velocity as a function of time is given by v =6t^2 i + 2t j where v is
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The concept of derivatives and integrals allows to find the results for the questions are the motion of a particle where the speed depends on time are:

       a)the position is:  r = 2 t³ i + t² j

       b) the position of the body on the y-axis is a parabola and on the x-axis it is a cubic function

       c) The acceleration is: a = 12 t i + 2 j

       d) the force is: F = 60 t i + 10 j

       e) the torque is:  τ = 40 t³ k^

       f) tha angular momentum is:  L = 4t³ - 6 t² k^

       g) The kinetic energy is: K = 2 m t² (9t² +1)

       h) The power is:   P = 2m (36 t³ + 2t)

Kinematics studies the movement of bodies, looking for relationships between position, speed and acceleration.

a) They indicate the function of speed.

        v = 6 t² i + 2t j

Ask the function of the position.   The velocity is defined by the variation of the position with respect to time

          v = \frac{dr}{dt}  

          dr = v dt

we substitute and integrate.

        ∫ dr = ∫ (6 t² i + 2t j) dt

        r - 0 = 6 \frac{t^3 }{3} \ \hat i + 2 \frac{t^2}{2 \ \hat j }  

       r = 2 t³ i + t² j

b) The position of the body on the y axis is a parabola and on the x axis it is a cubic function.

c) Acceleration is defined as the change in velocity with time.

           a = \frac{dv}{dt}  

           a = \frac{d}{dt} \ (6t^2 i + 2t j)  

           a = 12 t i + 2 j

d) Newton's second law states that force is proportional to mass times the body's acceleration.

          F = ma

          F = m (12 t i + 2 j)

          F = 5 12 t i + 2 j

          F = 60 t i + 10 j

e) Torque is the vector product of the force and the distance to the origin.

           τ = F x r

The easiest way to write these expressions is to solve for the determinant.

         \tau = \left[\begin{array}{ccc}i&j&k\\F_x&F_y&F_z\\x&y&z\end{array}\right]  

        \tau = \left[\begin{array}{ccc}i&j&k\\60t &10&0\\2t^3 &t^2&0\end{array}\right]  

       τ = (60t t² - 2t³ 10) k

       τ = 40 t³ k ^

f) Angular momentum

        L = r x p

        L =rx (mv)

        L = m (rxv)

The easiest way to write these expressions is to solve for the determinant.

       \left[\begin{array}{ccc}i&j&k\\2t^3 &t^2&0\\6t^2&2t&0\end{array}\right]  

    L = (4t³ - 6 t²) k

 

g) The kinetic energy is

            K = ½ m v²

            K = ½ m (6 t² i + 2t j) ²

            K = m 18 t⁴ + 2t²

            K = 2 m t² (9t² +1)

h) Power is work per unit time

           P = \frac{dW}{dt}dW / dt

The relationship between work and kinetic energy

           W = ΔK

     

          P = 2m \ \frac{d}{dt} ( 9 t^4 + t^2)

          p = 2m (36 t³ + 2t)

In conclusion with the concept of derivatives and integrals we can find the results for the questions are the motion of a particle where the speed depends on time are:

       a) The position is:  r = 2 t³ i + t² j

       b) The position of the body on the y-axis is a parabola and on the x-axis it is a cubic function

       c) The acceleration is: a = 12 t i + 2 j

       d) The force is: F = 60 t i + 10 j

       e) The torque is:  τ = 40 t³ k^

       f) The angular momentum is:  L = 4t³ - 6 t² k^

       g) The kinetic energy is: K = 2 m t² (9t² +1)

       h) The power is:   P = 2m (36 t³ + 2t)

Learn more here:  brainly.com/question/11298125

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