Awave has a wavelength of 4 × 10−7 m and a speed of 8 × 107 m/s in a particular material. what is its frequency in this material? answer in units of hz

According to the mathematical model, the wavelength has an inverse relationship with the frequency, the higher the frequency, the shorter the wavelength, and vice versa. The wavelength λ (lambda) is equal to the velocity v of the wave, divided by the frequency f:

For our case we have that

Replacing to find the frequency we have that

Therefore the frequency in this material is

graph question answered .. you think better when you are relaxed and happy

air exerts forces on falling objects near earth’s surface.

explanation:

the term 'free falls' refer to object that are falling towards the earth, in a situation in which gravity is the only force acting on the object.

for an object in free fall, the acceleration is constant (g, the gravitational acceleration), and so the velocity of the object constantly increases.

for objects near earth's surface, there is always another force acting on the object: the resistance due to the air. this force is opposed to the direction of fall of the object, and it is proportional to the velocity of the object, so as the object falls down, this force increases up to a point when it balances the force of gravity, and the object continues its motion at constant velocity (called terminal velocity). since in this case gravity is not the only force acting on the object, we are not in a situation of free fall.