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Andreyy89
3 years ago
14

A boy on rollerskates is travelling along at 8 m/s. He has a mass of 60 kg and is carrying his

Physics
1 answer:
Brrunno [24]3 years ago
5 0

Answer:

6m/s

Explanation:

the original momentum = mass x velocity = 8x (60+10) = 560

momentum after = mass x velocity of the school bag + mass x velocity of the boy = 10x20 + 60x A

200+60A = 560

A=6

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Car A is traveling west at 40 mi/h and car B is traveling north at 40 mi/h. Both are headed for the intersection of the two road
Gwar [14]

Explanation:

It is given that,

    \frac{dx}{dt} = -40 mi/h,     \frac{dx}{dt} = -40 mi/h

The negative sign indicates that x and y are decreasing.

We have to find \frac{dz}{dt}. Equation for the given variables according to the Pythagoras theorem is as follows.

              z^{2} = x^{2} + y^{2}

Now, we will differentiate each side w.r.t 't' as follows.

        2z\frac{dz}{dt} = 2x\frac{dx}{dt} + 2y\frac{dy}{dt}

or,          \frac{dz}{dt} = \frac{1}{z}(x\frac{dx}{dt} + y\frac{dy}{dt})

So, when x = 4 mi, and y = 3 mi then z = 5 mi.

As,       \frac{dz}{dt} = \frac{1}{z}(x\frac{dx}{dt} + y\frac{dy}{dt})

                       = \frac{1}{5}(4 \times (-40) + 3 \times (-40))

                       = \frac{-140 - 120}{5}

                       = 52

Thus, we can conclude that the cars are approaching at a rate of 52 mi/h.

7 0
3 years ago
A researcher measures the thickness of a layer of benzene (n = 1.50) floating on water by shining monochromatic light onto the f
NNADVOKAT [17]

Answer:

Explanation:

This problem relates to interference of light in thin films .

The condition of bright fringe in thin films which is sandwitched by two layers of medium having lesser refractive index  is as follows.

2nt = (2n+1) λ / 2  , n is refractive index of thin layer , t is its thickness ,  λ is wavelength of light .

2 x 1.5 t = λ / 2 , if n = 0 for minimum thickness.

2 x 1.5 t = 600 / 2 nm

t = 100 nm .

5 0
3 years ago
Which of these is a part of the biosphere? a. wind b. lakes c. bacteria d. glaciers
Aleks [24]
B. lakes is a part of the biosphere
Biosphere is defined as "<span>the regions of the surface, atmosphere, and hydrosphere of the earth (or analogous parts of other planets) occupied by living organisms." and a lake is the only thing on the list that could be occupied by a living thing.</span>
4 0
3 years ago
Read 2 more answers
Could we see a galaxy that is 20 billion light-years away?.
vichka [17]

Answer:

No

Explanation:

20 billion light-years away are beyond our sight and perspective on Earth and wouldn't be observable in our universe.

7 0
2 years ago
Suppose someone pours 0.250 kg of 20.0ºC water (about a cup) into a 0.500-kg aluminum pan with a temperature of 150ºC. Assume th
Troyanec [42]

Answer : The temperature when the water and pan reach thermal equilibrium short time later is, 59.10^oC

Explanation :

In this problem we assumed that heat given by the hot body is equal to the heat taken by the cold body.

q_1=-q_2

m_1\times c_1\times (T_f-T_1)=-m_2\times c_2\times (T_f-T_2)

where,

c_1 = specific heat of aluminium = 0.90J/g^oC

c_2 = specific heat of water = 4.184J/g^oC

m_1 = mass of aluminum = 0.500 kg = 500 g

m_2 = mass of water = 0.250 kg  = 250 g

T_f = final temperature of mixture = ?

T_1 = initial temperature of aluminum = 150^oC

T_2 = initial temperature of water = 20^oC

Now put all the given values in the above formula, we get:

500g\times 0.90J/g^oC\times (T_f-150)^oC=-250g\times 4.184J/g^oC\times (T_f-20)^oC

T_f=59.10^oC

Therefore, the temperature when the water and pan reach thermal equilibrium short time later is, 59.10^oC

8 0
3 years ago
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