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
Gnoma [55]
3 years ago
5

At its widest point, the diameter of a bottlenose dolphin is 0.50 m. Bottlenose dolphins are particularly sleek, having a drag c

oefficient of only about 0.090. a. What is the drag force acting on such a dolphin swimming at 7.5 m/s? b. Using the dolphin’s diameter as its characteristic length, what is the Reynolds number as it swims at this speed in 20° C water?
Physics
1 answer:
fiasKO [112]3 years ago
8 0

Answer:

497.00977 N

3742514.97005

Explanation:

\rho = Density of water = 1000 kg/m³

C = Drag coefficient = 0.09

v = Velocity of dolphin = 7.5 m/s

r = Radius of bottlenose dolphin = 0.5/2 = 0.25 m

A = Area

Drag force

F_d=\frac{1}{2}\rho CAv^2\\\Rightarrow F_d=\frac{1}{2}\times 1000 \times 0.09(\pi 0.25^2)7.5^2\\\Rightarrow F_d=497.00977\ N

The drag force on the dolphin's nose is 497.00977 N

at 20°C

\mu = Dynamic viscosity = 1.002\times 10^{-3}\ Pas

Reynold's Number

Re=\frac{\rho vd}{\mu}\\\Rightarrow Re=\frac{1000\times 7.5\times 0.5}{1.002\times 10^{-3}}\\\Rightarrow Re=3742514.97005

The Reynolds number is 3742514.97005

You might be interested in
Which among the following statements is correct?
Vinvika [58]

Answer:

C

Explanation:

Velocity is just speed with direction

5 0
3 years ago
Read 2 more answers
A 125-kg astronaut (including space suit) acquires a speed of 2.50 m/s by pushing off with her legs from a 1900-kg space capsule
ryzh [129]

(a) 0.165 m/s

The total initial momentum of the astronaut+capsule system is zero (assuming they are both at rest, if we use the reference frame of the capsule):

p_i = 0

The final total momentum is instead:

p_f = m_a v_a + m_c v_c

where

m_a = 125 kg is the mass of the astronaut

v_a = 2.50 m/s is the velocity of the astronaut

m_c = 1900 kg is the mass of the capsule

v_c is the velocity of the capsule

Since the total momentum must be conserved, we have

p_i = p_f = 0

so

m_a v_a + m_c v_c=0

Solving the equation for v_c, we find

v_c = - \frac{m_a v_a}{m_c}=-\frac{(125 kg)(2.50 m/s)}{1900 kg}=-0.165 m/s

(negative direction means opposite to the astronaut)

So, the change in speed of the capsule is 0.165 m/s.

(b) 520.8 N

We can calculate the average force exerted by the capsule on the man by using the impulse theorem, which states that the product between the average force and the time of the collision is equal to the change in momentum of the astronaut:

F \Delta t = \Delta p

The change in momentum of the astronaut is

\Delta p= m\Delta v = (125 kg)(2.50 m/s)=312.5 kg m/s

And the duration of the push is

\Delta t = 0.600 s

So re-arranging the equation we find the average force exerted by the capsule on the astronaut:

F=\frac{\Delta p}{\Delta t}=\frac{312.5 kg m/s}{0.600 s}=520.8 N

And according to Newton's third law, the astronaut exerts an equal and opposite force on the capsule.

(c) 25.9 J, 390.6 J

The kinetic energy of an object is given by:

K=\frac{1}{2}mv^2

where

m is the mass

v is the speed

For the astronaut, m = 125 kg and v = 2.50 m/s, so its kinetic energy is

K=\frac{1}{2}(125 kg)(2.50 m/s)^2=390.6 J

For the capsule, m = 1900 kg and v = 0.165 m/s, so its kinetic energy is

K=\frac{1}{2}(1900 kg)(0.165 m/s)^2=25.9 J

3 0
3 years ago
Which phenomena did Michael Faraday explore to help him invent the motor and the generator?
mamaluj [8]
The best and most correct answer among the choices provided by the question is the fourth choice. The phenomenon that Michael Faraday explored was electricity and magnetism. I hope my answer has come to your help. God bless and have a nice day ahead!
8 0
3 years ago
Read 2 more answers
If a car is moving to the left with constantvelocity, one can conclude that
jeka94

Answer:

The net force applied to the car is zero.

Explanation:

We are given that a car is moving to the left with constant velocity.

When the car moving with constant velocity

Then, the final velocity=Initial velocity

Change in velocity=Final velocity- initial velocity=0

When change in velocity is zero then , acceleration of car

a=\frac{change\;in\;velocity}{time}=\frac{0}{t}=0

When acceleration is zero then, By Newtons second law

Force=Mass\times acceleration=Mass\times 0=0

The net force applied on the car will be zero.

Option C:The net force applied to the car is zero.

5 0
3 years ago
If the velocity of gas molecules is doubled, then it’s kinetic energy will?( hint formula for kinetic energy is KE=.5 x mv2)
eduard

Answer:

D quadruple

Explanation:

E = \frac{1}{2}mv^2\\E'=\frac{1}{2}m(2v)^2=\frac{1}{2}m4 v^2 = 4(\frac{1}{2}mv^2)=4E

7 0
3 years ago
Read 2 more answers
Other questions:
  • ______ is the average _____ energy of the molecules in a object
    11·1 answer
  • You push against a steamer trunk with a force of 800 n at an angle alpha with the horizontal . the trunk is on a flat floor and
    8·1 answer
  • The word centripeta/means "<br> -seeking."<br> Answer here
    9·1 answer
  • A 0.89 m aqueous solution of an ionic compound with the formula mx has a freezing point of -3.0 ∘c . van't hoff factor?
    8·1 answer
  • To what tension must you adjust the string so that, when vibrating in its second overtone, it produces sound of wavelength 0.767
    13·1 answer
  • Definition of displacement
    10·1 answer
  • Use the drop-down menu to complete the statement. An electron in the first energy level of the electron cloud has an electron in
    12·2 answers
  • A 20 kg cart moving at 4 m/s has how much momentum?
    5·1 answer
  • Which is true of the greenhouse effect?
    5·1 answer
  • Help me please i dont understand
    13·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!