Which of the following statements is true about the nature of light?

Which of the following foods contains large amounts of protein? chicken, beans, fish, dairy, berries

d1i1m1o1n [39]

Answer: chicken hope this helps!

Explanation:

3 0

3 years ago

Read 2 more answers

a light wave travels from air into a medium of refractive index 1.54. If the wavelength of the light in air is 5.4 * 10^-7. calc

kozerog [31]

3.51 × 10^-7m

Explanation:

Refractive index = wavelength of the light in air ÷ wavelength in the medium

wavelength in the medium = wavelength of the light in air ÷ refractive index

= 5.4 * 10^-7 ÷ 1.54

= 3.51 × 10^-7m

3 0

3 years ago

A stunt driver wants to make his car jump over 8 cars parked side by side below a horizontal ramp.

Genrish500 [490]

<u>Answer:</u>

a) Minimum speed must he drive off the horizontal ramp = 39.78 m/s

b) Minimum speed must he drive off the horizontal ramp with 7° above the horizontal = 23.93 m/s

<u>Explanation:</u>

a) The height of ramp = 1.5 meter

Horizontal distance he must clear = 22 meter

The car is having horizontal motion and vertical motion. In case of vertical motion the acceleration on the car is acceleration due to gravity.

We have equation of motion, $s= ut+\frac{1}{2} at^2$ , s is the displacement, u is the initial velocity, a is the acceleration and t is the time.

In case of vertical motion initial velocity = 0 m/s, acceleration = 9.8 $m/s^2$ , we need to calculate time when displacement = 1.5 meter.

$1.5=0*t+\frac{1}{2} *9.8*t^2\\ \\ t = 0.553 seconds$

So the car has to cover a distance of 22 meter in 2.119 seconds.

So minimum speed required = 22/0.553 = 39.78 m/s

Minimum speed must he drive off the horizontal ramp = 39.78 m/s

b) When the take of angle is 7⁰ the vertical speed of car is not zero = V sin 7 = 0.122 V

So the in case of vertical motion we have initial velocity = 0.122 V, S = -1.5 meter( below ramp), acceleration = -9.8 $m/s^2$

Substituting

$-1.5=0.122V*t-\frac{1}{2} *9.8*t^2\\ \\ 4.9t^2-0.122Vt-1.5=0$

In case of horizontal motion

Horizontal speed of car = V cos 7 = 0.993V

So it has to travel 22 meter in t seconds

0.993Vt = 22, Vt = 22.155 m

Substituting in the equation $4.9t^2-0.122Vt-1.5=0$

We will get $4.9t^2-0.122*22.155-1.5=0\\ \\ t = 0.926 seconds$

Speed required = 22.155/0.926 = 23.93 m/s

Minimum speed must he drive off the horizontal ramp with 7° above the horizontal = 23.93 m/s

7 0

3 years ago

A 1.3-kg ball is attached to the end of a 0.8-m string to form a pendulum. This pendulum is released from rest with the string h

Natali5045456 [20]

Answer:

2.9 m/s

Explanation:

Momentum will be conserved

Speed of the ball just before collision is

v = √2gh = √(2(9.8)(0.8)) = 3.96 m/s

The initial momentum is 1.3(3.96) = 5.15 kg•m/s

The block takes away momentum of 0.6(2.2) = 1.32 kg•m/s

Leaving the ball with momentum of 5.15 - 1.32 = 3.83 kg•m/s

vf(ball) = 3.83 / 1.3 = 2.946... ≈ 2.9 m/s

3 0

3 years ago

An infinite long straight wire is uniformly charged, the charge density is a. Use Coulomb's law to calculate the electric field

bixtya [17]

Answer:

$\vec{E} = \frac{a}{2\pi \epsilon_0 R}\^R$

Explanation:

Since the wire is infinitely long, we will use Gauss' Law:

$\int\vec{E}d\vec{a} = \frac{Q_{enc}}{\epsilon_0}$

We will draw an imaginary cylindrical surface with height h around the wire. The electric flux through the imaginary surface will be equal to the net charge inside the surface.

In that case, the net charge inside the imaginary surface will be the portion of wire with height h. Then the charge of that portion will be equal to

$Q_{enc} = ah$

The left-hand side of the Gauss' Law is the flux through the imaginary surface. Since we choose our surface as a cylinder, of which we know the area, we do not have to take the surface integral.

$\int\vec{E}d\vec{a} = E2\pi R h$

where R is the radius of the imaginary cylinder.

Finally, Gauss' Law gives

$E2\pi Rh = \frac{ah}{\epsilon_0}\\E = \frac{a}{2\pi \epsilon_0 R}$

The vector expression is

$\vec{E} = \frac{a}{2\pi \epsilon_0 R}\^R$

As you can see, the electric field is independent from the height h, since that is merely an imaginary cylinder to apply Gauss' Law. In the end, what matters is the charge density of the wire and the distance from the wire.

4 0

4 years ago