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
MrRa [10]
3 years ago
12

To determine an athlete's body fat, she is weighed first in air and then again while she's completely underwater. it is found th

at she weighs 690 n when weighed in air and 48.0 n when weighed underwater. what is her average density?

Physics
2 answers:
Makovka662 [10]3 years ago
6 0

Her average density is about 1070 kg/m³

\texttt{ }

<h3>Further explanation</h3>

Let's recall Buoyant Force formula as follows:

\boxed{ F = \rho g V}

<em>where:</em>

<em>F = buoyant force ( N )</em>

<em>ρ = density of  fluid ( kg/m³ )</em>

<em>g = gravitational acceleration ( m/s² )</em>

<em>V = displaced body volume of liquid ( m³ )</em>

Let us now tackle the problem!

\texttt{ }

<u>Given:</u>

weight in air = w = 690 N

weight in underwater = w' = 48.0 N

density of water = ρ_w = 1000 kg/m³

<u>Asked:</u>

average density = ρ = ?

<u>Solution:</u>

<em>Firstly, we will calculate the volume of the athlete's body:</em>

w' = w - F

w' = w - \rho_w g V

\rho_w g V = w - w'

\boxed {V = ( w - w' ) \div ( \rho_w g )} <em>→ Equation 1</em>

\texttt{ }

<em>Next, we could calculate the average density of the athlete's body:</em>

\rho = m \div V

\rho = m \div [ ( w - w' ) \div ( \rho_w g ) ] <em>← Equation 1</em>

\rho = ( \rho_w m g) \div ( w - w' )

\rho = ( \rho_w w ) \div ( w - w' )

\rho = ( 1000 \times 690 ) \div ( 690 - 48.0 )

\boxed {\rho \approx 1.07 \times 10^3 \texttt{ kg/m}^3}

\texttt{ }

<h3>Learn more</h3>
  • Buoyant Force : brainly.com/question/13922022
  • Kinetic Energy : brainly.com/question/692781
  • Volume of Gas : brainly.com/question/12893622
  • Impulse : brainly.com/question/12855855
  • Gravity : brainly.com/question/1724648

\texttt{ }

<h3>Answer details</h3>

Grade: High School

Subject: Physics

Chapter: Pressure

il63 [147K]3 years ago
5 0

The difference in weight is due to the displacement of water (the buoyancy of water is acting on the athlete thus giving her smaller weight).<span>

The amount of weight displaced or the amount of buoyant force is: </span>

Fb = 690 N - 48 N

Fb = 642 N

From newtons law, F = m*g. Using this formula, we can calculate for the mass of water displaced:

m of water displaced = 642N / 9.8m/s^2

m of water displaced = 65.5 kg

Assuming a water density of 1 kg/L, and using the formula volume = mass/density:

V of water displaced = 65.5kg / 1kg/L = 65.5 L

The volume of water displaced is equal to the volume of athlete. Therefore:

V of athlete = 65.5 L

The mass of athlete can also be calculated using, F = m*g

m of athlete = 690 N/ 9.8m/s^2

m of athlete = 70.41 kg

 

Knowing the volume and mass of athlete, her average density is therefore:

average density = 70.41 kg / 65.5 L

<span>average density = 1.07 kg/L = 1.07 g/mL</span>

You might be interested in
A student conducts an experiment in which a cart is pulled by a variable applied force during a 2sec time interval. In trial 1,
Harlamova29_29 [7]

Answer:

change of momentum does not depend on the mass of the cars, as the force and time are the same all vehicles have the same change of momentum

Explanation:

Let's look for the speed of the car

     F = m a

    a = F / m

We use kinematics to find lips

    v = v₀ + a t

    v = v₀ + (F / m) t

The moment is defined by

    p = m v

The moment change

    Δp = m v - m v₀

Let's replace the speeds in this equation

    Δp = m (v₀ + F / m t) - m v₀

    Δp = m v₀  + F t - m v₀  

    Δp = F t

We see that the change of momentum does not depend on the mass of the cars, as the force and time are the same all vehicles have the same change of momentum

8 0
3 years ago
Distance travelled/time taken gives?
skad [1K]

Answer:

speed

Explanation:

Speed = distance travelled/time taken

6 0
3 years ago
Read 2 more answers
Why do individuals have different traits
Gwar [14]
Individuals have different traits because they are not twins so they should not  be alike also  because people have different genes witch would give them different traits. For example not every individual has blonde hair and blue eyes because they did not inherit those traits.
3 0
3 years ago
The small currents in axons corresponding to nerve impulses produce measurable magnetic fields. a typical axon carries a peak cu
Gemiola [76]

Answer:

6.66\cdot 10^{-12}T

Explanation:

The magnetic field produced by a current-carrying wire is given by

B=\frac{\mu_0 I}{2\pi r}

where

\mu_0 is the vacuum permeability

I is the current

r is the distance from the wire

In this problem we have

I=0.040 \mu A=4\cdot 10^{-8}A

r = 1.2 mm = 0.0012 m

So the magnetic field strength is

B=\frac{(4\pi \cdot 10^{-7} H/m)(4\cdot 10^{-8}A)}{2\pi (0.0012 m)}=6.66\cdot 10^{-12}T

5 0
3 years ago
The energy of the ball has been reduced by joules after bouncing back. This reduction happens because potential energy transform
luda_lava [24]
<span>This reduction happens because potential energy transforms to "thermal energy" and "sound energy"

Hope this helps!</span>
5 0
3 years ago
Other questions:
  • If a 2 kg ball is traveling at a speed of 4 m/s, what is its kinetic energy?
    7·2 answers
  • What is one way that early scientific practice differed from modern scientific practice?
    5·2 answers
  • A 38.0 kg child is in a swing that is attached to ropes 1.70 m long. The acceleration of gravity is 9.81 m/s 2 . Find the gravit
    13·1 answer
  • To understand the formula representing a traveling electromagnetic wave.
    14·1 answer
  • A total charge of 4.70 is distributed on two metal spheres. When the spheres are 10 cm apart, they each feel a repulsive force o
    8·1 answer
  • Please help ASAP I’ll give brainly and 10 points
    10·1 answer
  • What causes coastal erosion
    12·1 answer
  • When do we experience conservation of energy
    7·1 answer
  • A 2.8 kg rectangular air mattress is 2.00 m long, 0.500 m wide, and
    12·1 answer
  • Differentiate amihan and habagat
    8·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!