In a stormy sea, 2 waves pass a fixed point every second, and the waves are 10 meters apart. What is the speed of the wave?

When we greatly dim the light used in a double-slit experiment, we don’t simply get a dimmer interference pattern. What do we ge

maw [93]

Answer:

....... ....................

8 0

3 years ago

Scientists are working on a new technique to kill cancer cells by zapping them with ultrahigh-energy (in the range of 1012 W) pu

Tcecarenko [31]

1. $7.95\cdot 10^6 J$

The total energy given to the cells during one pulse is given by:

$E=Pt$

where

P is the average power of the pulse

t is the duration of the pulse

In this problem,

$P=1.59\cdot 10^{12}W$

$t=5.0 ns = 5.0\cdot 10^{-9} s$

Substituting,

$E=(1.59\cdot 10^{12}W)(5.0 \cdot 10^{-6}s)=7.95\cdot 10^6 J$

2. $1.26\cdot 10^{21}W/m^2$

The energy found at point (1) is the energy delivered to 100 cells. The radius of each cell is

$r=\frac{4.0\mu m}{2}=2.0 \mu m = 2.0\cdot 10^{-6}m$

So the area of each cell is

$A=\pi r^2 = \pi (2.0 \cdot 10^{-6}m)^2=1.26\cdot 10^{-11} m^2$

The energy is spread over 100 cells, so the total area of the cells is

$A=100 (1.26\cdot 10^{-11} m^2)=1.26\cdot 10^{-9} m^2$

And so the intensity delivered is

$I=\frac{P}{A}=\frac{1.59\cdot 10^{12}W}{1.26\cdot 10^{-9} m^2}=1.26\cdot 10^{21}W/m^2$

3. $9.74\cdot 10^{11} V/m$

The average intensity of an electromagnetic wave is related to the maximum value of the electric field by

$I=\frac{1}{2}c\epsilon_0 E^2$

where

c is the speed of light

$\epsilon_0$ is the vacuum permittivity

E is the amplitude of the electric field

Solving the formula for E, we find:

$E=\sqrt{\frac{2I}{c\epsilon_0}}=\sqrt{\frac{2(1.26\cdot 10^{21} W/m^2)}{(3\cdot 10^8 m/s)(8.85\cdot 10^{-12}F/m)}}=9.74\cdot 10^{11} V/m$

4. 3247 T

The magnetic field amplitude is related to the electric field amplitude by

$E=cB$

where

E is the electric field amplitude

c is the speed of light

B is the magnetic field

Solving the equation for B and substituting the value of E that we found at point 3, we find

$B=\frac{E}{c}=\frac{9.74\cdot 10^{11} V/m}{3\cdot 10^8 m/s}=3247 T$

3 0

3 years ago

An airplane of mass 1.60 ✕ 104 kg is moving at 66.0 m/s. The pilot then increases the engine's thrust to 7.70 ✕ 104 N. The resis

Ivan

(a) No, because the mechanical energy is not conserved

Explanation:

The work-energy theorem states that the work done by the engine on the airplane is equal to the gain in kinetic energy of the plane:

$W=\Delta K$ (1)

However, this theorem is only valid if there are no non-conservative forces acting on the plane. However, in this case there is air resistance acting on the plane: this means that the work-energy theorem is no longer valid, because the mechanical energy is not conserved.

Therefore, eq. (1) can be rewritten as

$W=\Delta K + E_{lost}$

which means that the work done by the engine (W) is used partially to increase the kinetic energy of the airplane ( $\Delta K$ ) and part is lost because of the air resistance ( $E_{lost}$ ).

(b) 77.8 m/s

First of all, we need to calculate the net force acting on the plane, which is equal to the difference between the thrust force and the air resistance:

$F=7.70\cdot 10^4 N - 5.00 \cdot 10^4 N=2.70\cdot 10^4 N$

Now we can calculate the acceleration of the plane, by using Newton's second law:

$a=\frac{F}{m}=\frac{2.70\cdot 10^4 N}{1.60\cdot 10^4 kg}=1.69 m/s^2$

where m is the mass of the plane.

Finally, we can calculate the final speed of the plane by using the equation:

$v^2- u^2 = 2aS$

where

$v=?$ is the final velocity

$u=66.0 m/s$ is the initial velocity

$a=1.69 m/s^2$ is the acceleration

$S=5.00 \cdot 10^2 m$ is the distance travelled

Solving for v, we find

$v=\sqrt{u^2+2aS}=\sqrt{(66.0 m/s)^2+2(1.69 m/s^2)(5.00\cdot 10^2 m)}=77.8 m/s$

8 0

3 years ago

Which of the following best describes magnetic fields? Question 4 options: Magnetic fields must have only positive charges. Magn

Kobotan [32]

<span> Magnetic fields have north and south magnetic poles.</span>

7 0

4 years ago

Read 2 more answers

What kind of motion will an object have when forces on it are balanced? (4 points)

Maslowich

Answer:

the object will not move at all because it is balanced is it was unbalanced it would move but since both forces to the object are balanced the object will never move

Explanation: SO TO SOME IT UP THE ANSWER IS ((A))

mark brainly plzz

5 0

3 years ago