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4 years ago

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The average human has a density of 945 kg/m3 after inhalation, and 1020 kg/m3 after exhalation. Fresh water has a density of 100

0 kg/3, sea water a density of about 1025 kg/m3, and the Dead Sea (which is actually a lake), a density of about 1230 kg/3. Which of the following statements are true?
a. The human body has nearly the same density as salt water after exhaling.
b. The human body will always float in the Dead Sea.
c.A human would float in fresh water after exhaling

1 answer:

Montano1993 [528]4 years ago

6 0

Answer:

a. The human body has nearly the same density as salt water after exhaling.

b. The human body will always float in the Dead Sea.

Explanation:

According to the concept of floating on the basis of density, any body that is put in a fluid of density greater than its own density will always float due to the force of buoyancy from the liquid.

The portion of the object submerged while the object is floating depends upon the density of the object as compared to the density of the fluid. This is governed by the equation:

$\rho_f.V_s=\rho_o.V_o$

where:

$\rho_f=$ density of the fluid

$\rho_o=$ density of the object

$V_s=$ volume of the object submerged in the fluid

$V_o=$ total volume of the object

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A car is moving north on a freeway. If a bug is flying south on the freeway, is the momentum of the bug positive or negative?

faltersainse [42]

Negative

Because the car is moving up and the bug is moving down. but it also depends on the weather so choice between one of those two I think is Negative but I may be wrong.

3 0

2 years ago

022 (part 1 of 4) 10.0 points A ball is thrown vertically upward with a speed of 24.5 m/s. How high does it rise? The accelerati

svetoff [14.1K]

1)

Answer:

Part 1)

H = 30.6 m

Part 2)

t = 2.5 s

Part 3)

t = 2.5 s

Part 4)

$v_f = 24.5 m/s$

Explanation:

Part 1)

initial speed of the ball upwards

$v_i = 24.5 m/s$

so maximum height of the ball is given by

$H = \frac{v_i^2}{2g}$

$H = \frac{24.5^2}{2(9.80)}$

$H = 30.6 m$

Part 2)

As we know that final speed will be zero at maximum height

so we will have

$v_f - v_i = at$

$0 - 24.5 = (-9.8)t$

$t = 2.5 s$

Part 3)

Since the time of ascent of ball is same as time of decent of the ball

so here ball will same time to hit the ground back

so here it is given as

t = 2.5 s

Part 4)

since the acceleration due to earth will be same during its return path as well as the time of the motion is also same

so here its final speed will be same as that of initial speed

so we have

$v_f = 24.5 m/s$

2)

Answer:

a = 9.76 m/s/s

Explanation:

As we know that the object is released from rest

so the displacement of the object in vertical direction is given as

$y = \frac{1}{2}at^2$

$4.88 = \frac{1}{2}a(1^2)$

$a = 9.76 m/s^2$

3)

Answer:

v = 29.7 m/s

Explanation:

acceleration of the rocket is given as

$a = 90 m/s^2$

time taken by the rocket

t = 0.33 min

final speed of the rocket is given as

$v_f = v_i + at$

$v_f = 0 + (90)(0.33)$

$v_f = 29.7 m/s$

4)

Answer:

Part 1)

y = 25.95 m

Part 2)

d = 6.72 m

Explanation:

Part 1)

As it took t = 2.3 s to hit the water surface

so here we will have

$y = \frac{1}{2}gt^2$

$y = \frac{1}{2}(9.81)(2.3^2)$

$y = 25.95 m$

Part 2)

Distance traveled by it in horizontal direction is given as

$d = v_x t$

$d = 2.92 \times 2.3$

$d = 6.72 m$

6 0

3 years ago

In the doorknob shown above, when the handle is rotated a distance of 189 millimeters, the spindle is rotated a distance of 27 m

Alisiya [41]

If my math is right its A) 7

because 189 divided by 27 is 7

7 0

4 years ago

Read 2 more answers

What combination of variables will make an experiment the most reliable

Virty [35]

Answer:

Explanation:

A combination of two controlled variables will make an experiment the most reliable.

Variables are the values that we take under any circumstance while doing an experiment so that we can keep on changing and get new results at the end.

It is important to have them in pair so that two values can be kept on changing in terms of any constant condition. This will help to get better results in over all experiment data.

4 0

3 years ago

Two men standing on the same side of wall and at the same distance from It, such that they are 4oom apart when one fires a gun t

Mamont248 [21]

Answer:

1. 571.43m/s

2. 142.9m and 342.9m

Explanation:

1.Take the difference in time.

1.2-0.7=0.7 seconds

Take the distance between them and divide with differnce in time.

400÷0.7=571.43 seconds.

2.Take the time of the two men and divide by two.

0.5÷2= 0.25 secs

1.2÷2= 0.6 secs

multiply each with the velocity.

0.25×571.43=142.9m

0.6×571.43=342.9m

8 0

2 years ago