What is the meaning of the safety symbol shown below?

Why is a control group generally very important in an experiment?

Alex17521 [72]

Answer: The control group is the part where you see what happens when you change a variable you want to study/examine. Basically, you need the control group because you need something to see what happens when you change something.

Hope this Helps! :))))

8 0

3 years ago

A distracted driver is driving towards a turn where the edge of the road leads into a 75.0 m cliff. The velocity of the vehicle

Vlada [557]

As long as the car is on the road, it moves with a constant speed of 80km/h.

As soon as the car starts to fall down the cliff, it follows a parabolic motion. It means that it still moves with constant speed along the x axis, but it also starts to move along the y axis, with constant acceleration (i.e. the acceleration due to gravity).

The good thing about parabolic motions is that the two motions along the x and y axes are completely separable.

So, first of all, we need to know how long it takes for an object to fall for 75m. The equation of a constantly accelerated motion is

$s=s_0+v_0t+\dfrac{1}{2}at^2$

Where $s_0$ is the initial position, $v_0$ is the initial speed, and $a$ is the constant rate of acceleration. In our case, we start from an initial height of 75m, an initial (vertical!) speed of zero, and our acceleration is $-g$ . So, our equation becomes

$s=75-\dfrac{g}{2}t^2$

And we want to solve for the time when $s=0$ (i.e. we want to know how long will it take for the object to reach the ground). We have

$0=75-\dfrac{g}{2}t^2 \iff 75=\dfrac{g}{2}t^2 \iff \dfrac{2\cdot75}{g}=t^2 \iff t=\sqrt{\dfrac{150}{g}}$

(I'm discarding the negative solution because it wouldn't make sense)

Now that we've used the vertical motion to find out the falling time, we can go back to the horizontal motion. We know that the car moves for a certain amount of time at a certain speed. So, we simply have to plug our values in the $s=vt$ equation, to get

$s=80\sqrt\dfrac{150}{g}}$

This is how far from the base of the cliff the vehicle lands.

3 0

3 years ago

The intensity of light from a central source varies inversely as the square of the distance. If you lived on a planet only half

sertanlavr [38]

Answer:

the intensity will be 4 times that of the earth.

Explanation:

let us assume the following:

intensity of light on earth =J

distance of earth from sun = d

intensity of light on other planet = K

distance of other planet from sun = $\frac{d}{2}$ (from the question, the planet is half as far from the sun as earth)

from the question the intensity is inversely proportional to the square of the distance, hence

intensity on earth : J = $\frac{1}{d^{2} }$

J $d^{2}$ = 1 ... equation 1

intensity on other planet : K = $\frac{1}{(\frac{d}{2}) ^{2} }$ (the planet is half as far from the sun as earth)

K $(\frac{d}{2}) ^{2}$ = 1 ....equation 2

equating both equation 1 and 2 we have

J $d^{2}$ = K $(\frac{d}{2}) ^{2}$

J $d^{2}$ = K $\frac{d^{2}}{4}$

J = $\frac{K}{4}$

K = 4J

intensity of light on other planet (K) = 4 times intensity of light on earth (J)

5 0

3 years ago

In which type of Eclipse do u see the Sun in the form of a ring

Helga [31]

The type of eclipse in which one sees the sun in the form of a ring is ANNULAR SOLAR ECLIPSE.
Solar eclipse occurs when the moon casts a shadow on the earth.
There are three basic types of solar eclipse, these are total, partial and annular solar eclipse. The annular solar eclipse occurs when the moon covers the sun's center thereby leaving the sun visible outer edges to form a ring of fire around the moon.<span />

8 0

3 years ago

Describe the valence electrons in nitrogen and how it could bond to other atoms?

Gekata [30.6K]

Answer:

Each nitrogen molecule consists of two atoms of nitrogen that are bonded by a triple covalent bond. This is because each nitrogen atom has 5 valence electrons. Each atom can complete its octet by sharing three electrons.

I hope this helps!

4 0

3 years ago