1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
den301095 [7]
3 years ago
12

meg runs a 10-km race in 45 minutes (0.75 hours). what was her speed in kilometers per hour ? a. 7.5 km/hr b. 4.5 km/hr c. 13 km

/hr d. 22 km/hr
Physics
1 answer:
cricket20 [7]3 years ago
3 0
The answer would be C.
You might be interested in
A car moves at speed v across a bridge made in the shape of a circular arc of radius r. (a) Find an expression for the normal fo
inna [77]

Answer:

(a) FN = m (g - \frac{v^{2} }{r})

(b) vmin = 17.146 m/s

Explanation:

The radius of the arc is

r = 30m

The normal force acting on the car form the highest point is

FN = m (g - \frac{v^{2} }{r})

If the normal force become 0 we have

m (g - \frac{v^{2} }{r}) = 0

or

g - \frac{v^{2} }{r} = 0

This way, when FN = 0, then v = vmin, so

g - \frac{vmin^{2} }{r} = 0

vmin = \sqrt[.]{g*r} = \sqrt[.]{9.8 m/s^{2} * 30m } = 17.146 m/s

4 0
4 years ago
A 37-cm-long wire of linear density 18 g/m vibrating at its second mode, excites the third vibrational mode of a tube of length
lora16 [44]

Answer:

T = 4.42 10⁴ N

Explanation:

this is a problem of standing waves, let's start with the open tube, to calculate the wavelength

        λ = 4L / n                 n = 1, 3, 5, ...    (2n-1)

How the third resonance is excited

       m = 3

       L = 192 cm = 1.92 m

       λ = 4 1.92 / 3

       λ = 2.56 m

As in the resonant processes, the frequency is maintained until you look for the frequency in this tube, with the speed ratio

      v = λ f

      f = v / λ

      f = 343 / 2.56

      f = 133.98 Hz

       

Now he works with the rope, which oscillates in its second mode m = 2 and has a length of L = 37 cm = 0.37 m

The expression for standing waves on a string is

           λ = 2L / n

           λ = 2 0.37 / 2

           λ = 0.37 m

The speed of the wave is

          v = λ f

As we have some resonance processes between the string and the tube the frequency is the same

          v = 0.37 133.98

          v = 49.57 m / s

Let's use the relationship of the speed of the wave with the properties of the string

              v = √ T /μ

              T = v² μ

              T = 49.57²   18

              T = 4.42 10⁴ N

4 0
3 years ago
Read 2 more answers
A sphere with a charge q is fixed at the bottom left corner of the right triangle shown in the figure. Points P and R are at the
Alexus [3.1K]

Answer:

the final potential energy of this system is 3U0/10

Explanation:

We are given

charge at left end  and another test charge at point p

Potential energy is given by  = \frac{k*Q1*Q2 }{R}

where k is electrostatics constant = 9 *10^9

Q1 = first charge , Q2=  test charge

R= distance between charges

potential at point p

U0 = k*Q1*Q2 /3 ⇒ kq1q2 = 3U0 ..............1

now the test charge moves to point R

using Pytahgoreou theorem

R(distance) = \sqrt{8^2 + 6^2} = 10

New Potential energy

U1 = kq1*q2 / 10

substituting  kq1q2 = 3U0 from 1

U1 = 3U0/10

So this is the final potential energy of this system.

5 0
3 years ago
Compare relative age with absolute age.
oee [108]

Answer & Explanation:

Relative age is the age of a rock layer (or the fossils it contains) compared to other layers. It can be determined by looking at the position of rock layers. Absolute age is the numeric age of a layer of rocks or fossils.

8 0
3 years ago
In a elastic lab what did you change and why?
Vilka [71]

I changed my undershorts.  The elastic on the old ones I put on that day was deteriorated, and it completely failed when I dripped lab coffee on it, causing falldown.

7 0
3 years ago
Read 2 more answers
Other questions:
  • Two charged objects are separated by some distance. the charge on the first object is greater than the charge on the second obje
    5·2 answers
  • A battery sits in an iPod before the iPod is turned on.
    12·2 answers
  • What speed must an electron have if its momentum is to be the same as that of an x-ray photon with a wavelength of 0.20 nm?
    10·1 answer
  • Please help.
    14·2 answers
  • Give 2 examples of mountain ranges in the world that have been caused by folding
    7·1 answer
  • A block of mass m = 0.13 kg is set against a spring with a spring constant of k1 = 623 N/m which has been compressed by a distan
    8·1 answer
  • Define temperature<br> define absolute zero
    9·1 answer
  • A 75 kg football player is gliding forward across very smooth ice at 4.6 m/s. He throws a 0.47 kg football straight forward. A)
    13·1 answer
  • Explain how Earth can be in the middle of an ice age at the same time it is experiencing global warming.
    7·1 answer
  • What factors do NOT affect friction between two objects? Explain how you know this.
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!