Da 6.0 kg wooden crate slides across a wooden floor

You are standing outside during the daytime. How can you see a blade of grass?

pashok25 [27]

Answer:

C: Light travels from the Sun to the grass and is then reflected to your eyes.

Explanation:

Our eyes don't produce light but detect light (so answer A is not correct)

The grass doesn't produce light unless it is burning (discard answer B)

Answer C is the correct one.

The light we detect from the grass is not light bounced off the sky, it comes directly from the grass to your eyes (you are not looking at the sky when you see the grass) Discard answer D

8 0

3 years ago

Read 2 more answers

A satellite in geostationary orbit is used to transmit data via electromagnetic radiation. The satellite is at a height of 35,00

Aleksandr-060686 [28]

Answer:

Explanation:

We have the following relation between power, P and intensity, I

$I = P/(4*pi*r^2)$

= $10^3/(4*pi*(35000*10^3))$

= $6.5*10^-14 W/M^2$

We also have the following relationship between electric field and electromagnetic radiation thus

$I = (ceE^2)/2$

Hence $E = \sqrt{2I/ce}$

substituting the values of I, c and e, we have

$7*10^-6 V/m$

3 0

3 years ago

In 2007, michael carter (u.s.) set a world record in the shot put with a throw of 24.77 m. what was the initial speed of the sho

Serga [27]

The initial speed of the shot is 15.02 m/s.

The Shot put is released at a height y<em> </em>from the ground with a speed u. It is released at an angle θ to the horizontal. In a time t, the shot put travels a distance <em>R</em> horizontally.

Pl refer to the attached diagram.

Resolve the velocity u into horizontal and vertical components, u ₓ=ucosθ and uy=u sinθ. The horizontal component remains constant in the absence of air resistance, while the vertical component varies due to the action of the gravitational force.

Write an expression for R.

$R=u_xt=(ucos \theta)t$

Therefore,

$t=\frac{R}{ucos\theta} .......(1)$

In the time t, the net displacement of the shotput is y in the downward direction.

Use the equation of motion,

$y=u_yt-\frac{1}{2}gt^2=(usin\theta) t-\frac{1}{2}gt^2$

Substitute the value of t from equation (1).

$y=(ucos\theta)(\frac{R}{ucos\theta} )-\frac{1}{2} g(\frac{R}{ucos\theta} )^2\\ =Rtan\theta-(\frac{gR^2}{2u^2cos^2\theta} )$

Substitute -2.10 m for y, 24.77 m for R and 38.0° for θ and solve for u.

$y=Rtan\theta-(\frac{gR^2}{2u^2cos^2\theta} )\\ (-2.10m)=(24.77 m)(tan38.0^o)-\frac{(9.8 m/s^2)(24.77m)^2}{2u^2(cos38.0^o)^2} \\ u^2=225.71(m/s)^2\\ u=15.02m/s$

The shot put was thrown with a speed 15.02 m/s.

7 0

3 years ago

Elements in a period have _____________.

ahrayia [7]

Answer:

Elements in a period have wide range of chemical properties.

Explanation:

Period is the row of chemical elements's arrangement in the periodic table. It is numbered from 1 to 7.
In period as we move towards right the atomic number of element constantly increases along with the change in chemical properties.
As we move from left towards right in period, the valence electron number regularly increases in every element.
This valence electron differs the reactivity of the elements.

6 0

3 years ago

How much energy is required to move 2 electrons through a potential difference of 1.0 x 10^ 2 volts?

Ksenya-84 [330]

Charge of electron = 1.6×10−¹⁹

(1.6×10−¹⁹)(1×10²) (2e)

= 3.2×10−¹⁷ J

3 0

3 years ago