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Digiron [165]
3 years ago
11

An object weigh 40N in air ,weigh 20N when submerged in water,and 30N when submerged in a liquid of unknown liquid density.what

is the density of unknown of liquid?
Physics
1 answer:
muminat3 years ago
7 0

Answer:

The density is  \rho_u  =500 kg /m^3

Explanation:

From the question we are told that

    The weight in air is  W_a =  40 \ N

     The weight in water is  W_w =  20 \ N

     The weight in a unknown liquid is  W_u  =  30  \ N

Now according to Archimedes principle the weight of the object in water is mathematically represented as

       W_w =  W_a -m _w g

Where  m_w is he mass of the water displaced

 substituting value

       m_w g  =  40 -20

      m_w g  = 20 \ N --- (1)

Now according to Archimedes principle the weight of the object in unknown  is mathematically represented as

       W_u =  W_a -m _u g

Where  m_u is he mass of the unknown liquid  displaced

 substituting value

       m_u g  =  40 -30

      m_u g  = 10 \ N ---(2)

dividing equation 2 by equation 1

      \frac{m_ug}{m_wg}  =  \frac{10}{20}

     \frac{m_u}{m_w}  =  \frac{1}{2}

=>  m_u =  0.5 m_w

Now since the volume of water and liquid displaced are the same then

      \rho _u =  0.5 \rho_w

This because

         density =  \frac{mass}{volume}

So if  volume is constant

         mass = constant * density

Where \rho_u is the density of the liquid

     and  \rho_ w is the density of water which is a constant with a value \rho_w = 1000 kg/m^3

So

        \rho_u  = 1000*0.5

        \rho_u  =500 kg /m^3

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Nina [5.8K]

Answer:

1 × 10⁶ N/C

Explanation:

The magnitude of the electric field between the membrane = surface density / permittivity of free space = 10 ⁻⁵C/ m² / (8.85 × 10⁻¹²N⁻¹m⁻²C²) = 1.13 × 10⁶ N/C approx 1 × 10⁶ N/C

4 0
3 years ago
A paper airplane is thrown to the north from the top of a cliff with a speed of 2 km/h. The paper airplane lands 15 minutes (0.2
Luden [163]
If you neglect air resistance, then you can solve for the horizontal distance using the formula:

dx=vixt

Where:
dx = horizontal distance
vix = initial horizontal velocity
t = time in flight

Now you can see that you have all the given you need. 
vix= 2km/h
t = 0.25 hours

We use hours because you need the units to be the same. So just plug that in your equation and you will have your answer:

dx = vixt
     =(2km/h)(0.25h)
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This means that the answer to your question is B.
5 0
3 years ago
Is my answer correct plz explain i don't understand it.
lora16 [44]

Answer:

yes that is correct

Explanation:

4 0
3 years ago
a car begins at rest at a stoplight. After the light turns green, the car begins to accelerate 5 m/s squared over the span of 3.
gogolik [260]

Answer: 9m

Explanation:

Our given:

Acceleration- 5m/s^2

Time- 3.6 seconds

Use the equation d = 1/2 • a • t^2

d = 1/2 • 5m/s^2 • 3.6 secs

d = 2.5m/s^2 • 3.6 secs

d = 9m

I hope this is correct

4 0
3 years ago
A cyclist is riding along at a constant velocity of 15 m/s. he then accelerates at a uniform rate of 0.50 m/s2 over a distance o
kotegsom [21]

<u>Answer: </u>

Cyclist will take 4 seconds to travel 64 meter.

<u>Explanation: </u>

 We have equation of motion, s= ut+\frac{1}{2} at^2, s is the displacement, u is the initial velocity, a is the acceleration and t is the time.

 In this case initial velocity = 15 m/s, acceleration = 0.50 m/s^2, we need to calculate time when displacement = 64 meter.

 Substituting

64=15*t+\frac{1}{2} *0.50*t^2\\ \\ t^2+60t-256=0\\ \\ (t-4)(t+64)=0

 t = 4 seconds or t = -64 seconds(which is not possible).

So he will take 4 seconds to travel 64 meter.


6 0
3 years ago
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