Higher frequency electromagnetic waves have ?

What happens when an unstoppable force meets an immovable object?

AlladinOne [14]

The unstoppable object will stop regardless.

7 0

2 years ago

La pregunta dice asi: de las acciones politicas que pone como ejemplo norberto bobbio, elija una y expliquela

Ksivusya [100]

Quisiera ayudarte pero no puedo apenas voy a pasar a secundaria :(

5 0

3 years ago

Lucy and her bike together have a mass of 120kg. She slows down from 4.5m/s to 3.5m/s. How much kinetic energy does she lose?

vovangra [49]

The kinetic energy of a moving object is given by
$K= \frac{1}{2}mv^2$
where m is the object's mass and v its velocity.

In our problem, the initial kinetic energy is:
$K_i = \frac{1}{2} m v_i^2 = \frac{1}{2}(120 kg) (4.5 m/s)^2=1215 J$

while the final kinetic energy is:
$K_f = \frac{1}{2}mv_f^2 = \frac{1}{2}(120 kg)(3.5 m/s)^2= 735 J$

So, the kinetic energy lost by Lucy and her bike is
$\Delta K = K_i - K_f = 1215 J - 735 J = 480 J$

7 0

3 years ago

Tropospheric ozone ________.

Nata [24]

Tropospheric ozone is produced through interaction of heat and UV light, with nitrogen oxides and carbon containing compounds.

Option: D

Explanation:

In earth's atmosphere there are total five layers: Troposphere, Stratosphere, Mesosphere, Ionosphere and Exosphere. Stratosphere is known as Ozonosphere where ozone layer is present with the key constituent ozone. Ozone layer is very important as it protects whole environment from harmful UV rays coming from space.

Tropospheric ozone is produced through the interaction of heat and UV light with nitrogen oxides and carbon containing compounds. Ozone plays a dual role in environment when it is in lower surface area it is a harmful gas and when it is in atmospheric layer it is a life saving layer.

4 0

3 years ago

The block of weight 113 lb is pushed with a force of P = 31 lb on top of two cylindrical rollers with a weight of 42 lb and a ra

Lilit [14]

Answer:

The block's speed will be of 5,1 ft/s

Explanation:

For this problem solve it is used the work and energy theorem which state:

$W=dK$

Where W is the net work done and dK the change in the kinetic energy between in the time after and before the force is applied. The net work can expressed as:

$W=F.d$

Here F and d are applied force and the displacement. While the kinetc energy for the i body:

$Ki=1/2*m_{1}V_{1}^2+1/2*I_{1}w_{1}^2$

Where mi,Ii Vi, wi are the mass, the moement of inertia, the linear and the angular velocity for the i body respectively. Therefore to calcule the total change in kinetic energy we take into account all the bodies involves, in this case the block and the two rollers. Assuming fixed rollers but can rotate, and the block with linear movement, the final kinect energy is:

$Kf=1/2*m_{b}V_{b}^2+1/2*I_{r1}w_{r1}^2+1/2*I_{r2}w_{r2}^2$

Note since at the beginning the bodies system is at rest hence the initial kinetic energy is null. In the above equation the subscripts b, r1 and r2 relate to the block and the two rollers.

For solid roller the moment of inertia can be calculated as:

$I_{r}=1/2*m_{r}R_{r}$

Where mr and Rr are the mass and radius rollers. Replacing the moment of inertia in the kinetic energy:

$Kf=1/2*m_{b}V_{b}^2+1/4*m_{r1}R_{r1}w_{r1}^2+1/4*m_{r2}R_{r2}w_{r2}^2$

As at the point of contact there is no displacement between the surfaces of the block and the rollers, in that point the linear velocities of this bodies are the same. So can expressed the linear velocity of the block as function of the rotating speed and the rollers radius:

$V_{b}=w_{r}R$

Entering latest in the new kinetic energy expression:

$Kf=1/2*m_{b}.(w_{r}.R)^2+1/4*m_{r}Rw_{r}^2+1/4*m_{r}Rw_{r}^2$

By doing this the kinetic energy expressed only as function of the roller rotating speed. As the roller rotatings speed are the same, and the masses and the radius are known, the the kinetic energy can expressed as:

$Kf=1/2*113\ lb.\1.57\ ft\ w^2+1/4*42\ lb.\ 1.57\ ft\ w^2+1/4*42\ lb.\ 1.57\ ft\ w^2$