Ask question

Ask question

All categories

grandymaker [24]

3 years ago

7

In using the drag coefficient care needs to be taken to use the correct area when determining the drag force. What is a typical

example of the appropriate area to use?

1 answer:

stealth61 [152]3 years ago

6 0

Answer:

Explanation:

We know that Drag force $F_D$

$F_D=\dfrac{1}{2}C_D\rho AV^2$

Where

$C_D$ is the drag force constant.

A is the projected area.

V is the velocity.

ρ is the density of fluid.

Form the above expression of drag force we can say that drag force depends on the area .So We should need to take care of correct are before finding drag force on body.

Example:

When we place our hand out of the window in a moving car ,we feel a force in the opposite direction and feel like some one trying to pull our hand .This pulling force is nothing but it is drag force.

You might be interested in

Two standard spur gears have a diametrical pitch of 10, a center distance 3.5 inches and a velocity ratio of 2.5. How many teeth

lubasha [3.4K]

Answer:50 , 20

Explanation:

Given

Diametrical Pitch $\left ( P_D\right )=\frac{T}{D}$

where T= no of teeths

D=diameter

module(m) of gears must be same

$m=\frac{D}{T}=\frac{1}{P_D}=0.1$

Let $T_1 & T_2$ be the gears on two gears

Therefore Center distance is given by

$m\frac{\left ( T_1+T_2\right )}{2}=3.5$

thus

$0.1\frac{\left ( T_1+T_2\right )}{2}=3.5$

$T_1+T_2=70----1$

and Velocity ratio is given by

$VR=\frac{No\ of\ teeths\ on\ Driver\ gear}{No.\ of\ teeths\ on\ Driven\ gear}$

$2.5=\frac{T_1}{T_2}----2$

From 1 & 2 we get

$T_1=50, T_2=20$

6 0

3 years ago

In alternating current, how often does the current alternate between negatively and postively?

Serggg [28]

In an alternating current (AC) circuit the two poles alternate between negative and positive and the direction of the current (electron flow) reverses periodically.

4 0

2 years ago

Read 2 more answers

A girl operates a radio-controlled model car in a vacant parking lot. The girl's position is at the origin of the xy coordinate

lawyer [7]

Answer:

a) 17.20

b) 11.31

c) 14.42

d) 12.65

Explanation:

(a)

The girl is at the origin of the x,y coordinates (i.e 0,0,0 )

the position vector of the car at time 't' secs is

$\vec{r}= 2+2t^2, 6+t^3,0$

at t=2s, the position vector is

$\vec{r}= 10, 14,0$

Therefore, the the distance between the car and the girl is

$s= \sqrt{(10-0)^2+(14-0)^2+(0-0)^2)}\$

s = 17.20

(b)

The position of the car at t = 0s is $\vec{r}_0 = 2,6,0$

The position of the car at t = 2s is $\vec{r}_2 = 10,14,0$

The distance of the car traveled in the interval from t=0s to t=2 s is as follows:

$s_{02}= \sqrt{(10-2)^2+(14-6)^2+(0-0)^2)} \\ \\ s_{02} = 11.31$

(c)

The position vector of the car at time 't' secs is

$\vec{r}= 2+2t^2, 6+t^3,0$

The velocity of the car is

$\vec{v}=\dfrac{d\vec{r}}{dt}= 4t, 3t^2,0$

the direction of the car's velocity at t = 2s is going to be

$\vec{v}\mid _t=2 8, 12,0$

Thus; The speed of the car is

$v_{t=2}= \sqrt{8^2+12^2+0^2} \\ \\ v_{t=2}= 14.42$

(d) the car's acceleration is:

$\vec{a}=\frac{d\vec{v}}{dt}= 4, 6t,0$

The magnitude of car's acceleration at t=2s is

$\mid \vec{a}\mid _{t=2}=\sqrt{4^2+12^2+0^2} \\ \\ \mid \vec{a}\mid _{t=2}= 12.65$

5 0

3 years ago

Which of the following tasks are performed by the marketing department:

Sloan [31]

Answer:B

Explanation

8 0

2 years ago

You need to own your own printer in order to join the 3D printing movement <br><br> True or False

Nata [24]

Answer:

False

Explanation:

7 0

3 years ago