Which type of water body does water move the slowest?

What does the energy of an electromagnetic wave depend on?

Mrrafil [7]

It depends on frequency

6 0

3 years ago

(a) what is the system of interest if the acceleration of the child in the wagon is to be calculated? (select all that apply.)

Leno4ka [110]

since child is moving along with the wagon and we need to find the acceleration of child inside that wagon then in this case the system of interest must be child + wagon

System of interest will be the system that is used to find the force or acceleration using Newton's law

Here we have to assume that system on which if we will calculate the forces then the net value of force on that system will help to calculate the unknown quantities

So here our system will be boy + wagon

6 0

3 years ago

A worker does 25 J of work lifting a bucket, then sets the bucket back down in the same place. What is the total net work done o

Vera_Pavlovna [14]

Answer:

0 J

Explanation:

As work is force times displacement, if no displacement occurs, no work occurs.

5 0

2 years ago

6) Find the speed a spherical raindrop would attain by falling from 4.00 km. Do this:a) In the absence of air dragb) In the pres

sleet_krkn [62]

We are asked to determine the velocity of a rain drop if it falls from 4 km.

To do that we will use the following formula:

$2ah=v_f^2-v_0^2$

Where:

$\begin{gathered} a=\text{ acceleration} \\ h=\text{ height} \\ v_f,v_0=\text{ final and initial velocity} \end{gathered}$

If we assume the initial velocity to be 0 we get:

$2ah=v_f^2$

The acceleration is the acceleration due to gravity:

$2gh=v_f^2$

Now, we take the square root to both sides:

$\sqrt{2gh}=v_f$

Now, we substitute the values:

$\sqrt{2(9.8\frac{m}{s^2})(4000m)}=v_f$

solving the operations:

$280\frac{m}{s}=v$

Therefore, the velocity without air drag is 280 m/s.

Part B. we are asked to determine the velocity if there is air drag. To do that we will use the following formula:

$F_d=\frac{1}{2}C\rho_{air}Av^2$

Where:

$\begin{gathered} F_d=drag\text{ force} \\ C=\text{ constant} \\ \rho_{air}=\text{ density of air} \\ A=\text{ area} \\ v=\text{ velocity} \end{gathered}$

We need to determine the drag force. To do that we will use the following free-body diagram:

Since the velocity that the raindrop reaches is the terminal velocity and its a constant velocity this means that the acceleration is zero and therefore the forces are balanced: