Levi decides to examine the effect of fertilizer on the growth of tomato plants. He chooses four plants for his experiment and applies varying amounts of fertilizer to the three of them. He does not apply fertilizer to one plant.


Over a 15-day period, the plants receive fertilizer on Days 1, 4, 7, 10, and 13. Levi measures the height of all of his plants with a meter stick on Days 3, 6, 9, 12, and 15. He also makes sure to hold all experimental factors constant except for the fertilizer.



Which statement describes what Levi did to prepare the control group in his experiment?



Levi applied different amounts of fertilizer to three of his plants.

Levi did not apply any fertilizer to one of his plants..

Levi held all experimental factors constant except for fertilizer., ,

Levi measured his plants on five separate days.

Answer:

I don't really know much about the whole stars thing, but I've written a lot of paragraphs in science

Explanation:

Remember:

Include:

Answer:

Option C

Explanation:

Centripetal acceleration formula regarding velocity and radius is,

[tex]a_c=\frac{v^2}{r}[/tex]

now we know the centripetal acceleration is 9 and the radius is 16 so we plug these values into our formula,

[tex]a_c=\frac{v^2}{r}\\\\9=\frac{v^2}{16} \\\\144=v^2\\\\\sqrt{144}=v \\\\v=12\ m/s[/tex]

so velocity is 12 m/s

Now for the angular velocity, the formula of centripetal acceleration regarding angular velocity and radius is,

[tex]a_c=rw^2[/tex]

we know the centripetal acceleration is 9 and the radius is 16 so plug these values into the formula,

[tex]a_c=rw^2\\\\9=16w^2\\\\0.5625=w^2\\\\\sqrt{0.5625}=w \\\\0.75\ rad/s=w\\[/tex]

so angular velocity is 0.75 rad/s

Answer: The pressure exerted on a surface by an object increases as the surface area of contact decreases.

Explanation:

Pressure measures the amount of force exerted per a given area of an object. From this definition, the surface area of the object and force applied, affects the pressure applied.

As Benny presses his finger against a map, nothing happens to the map because the force applied is affected by the increased surface area of his finger. However as he presses a thumbtack into the map using the same force the tack will probably poke a hole in the map because the small( decreased) surface area of the sharp point of the thumbtack produces a much larger pressure on the map than the area of Benny finger. I hope this helps, thanks!

Answer:

The sea bed is 1125 m deep.

Explanation:

Speed

It's the rate of change of the distance (d) traveled by an object over time (t).

The speed can be calculated by the formula:

[tex]\displaystyle v=\frac{d}{t}[/tex]

It's known the speed of sound in water is v=1500 m/s. A sound wave is sent to the sea bed and bounces back to the ship 1.5 seconds later.

That is the time the wave takes to travel twice the distance from the ship to the sea bed, thus the required distance uses half of that time or t=1.5/2 = 0.75 seconds.

Solving the equation for d:

d = v.t

d = 1500 m/s * 0.75 s

d = 1125 m

The sea bed is 1125 m deep.

Answer:

Difference is given below.

Explanation:

The main difference between beneficial and harmful friction is that beneficial friction is necessary for performing different activities while on the other hand, harmful effect of friction is destroy different parts of products and machines. examples of beneficial friction are walking, holding things, rubbing hands to produce heat, running etc whereas examples of harmful friction are destruction of sole, slipping, tearing of machine's part, Wet roads and Mudslides etc.

Answer:

Explanation:

The resistance of this device is determined by using the formuia from Ohms Law:

V = IR

where; V = voltage

I = current

R = resistance

From the above equation:

R = V/ I ---- (1)

And

I = P/V    --- (2)

If 1 unit = 1 KWH = 3.6 × 10⁶ J

Then;

2.2 units = (3.6 × 10⁶ × 2.2)

= 7.92 × 10⁶ J

So, Energy = 7.92 × 10⁶ J

Also:

Power = energy/time

Power =  7.92 × 10⁶ J / 1 hour

Power = 7.92 × 10⁶ J / 3600 seconds

Power = 2200 Watts

From equation (2)

I = P/V

I = 2200/220

I = 10 A

Recall that:

Resistance R = V/I

Resistance R = 220/10

Resistance R = 22 ohms

SO, if 1 unit costs = Ts 6.00

Then the cost of 2.2 unit = 2.2 ( Rs  6.00)

= Rs 13.20

Answer:

When a body is in uniform circular motion, its speed remains constant but its velocity, angular acceleration, angular velocity changes due to change in its direction.

Answer:

The ratio is  [tex]k:d = 1 : 5[/tex]

Explanation:

From the question we are told that

   The first minimum of the single slit pattern falls on the fifth maximum of the double slit pattern.

Generally the condition for constructive interference for as single slit is  

     [tex]ksin(\theta) = n\lambda[/tex]

Here  k is the width of the slit  and n is the order of the fringe and for single slit n =  1 (cause we are considering the first maxima)

Generally the condition for constructive interference for as double slit is    

        [tex]dsin\theta = m\lambda[/tex]

Here  d is the separation between the  slit  and m is the order of the fringe and for double slit  m  =  5  (cause we are considering the first maxima)

=>     [tex]dsin\theta = 5\lambda[/tex]

So

       [tex]\frac{ksin(\theta)}{dsin(\theta)} = \frac{\lambda}{5\lambda}[/tex]

=>    [tex]\frac{k }{d} = \frac{1}{5}[/tex]

So  

      [tex]k:d = 1 : 5[/tex]

Answer:

Explanation:

The kinetic energy of an object can be found by using the formula

[tex]k = \frac{1}{2} m {v}^{2} \\ [/tex]

m is the mass

v is the velocity

From the question we have

[tex]k = \frac{1}{2} \times 75 \times {7}^{2} \\ = 37.5 \times 49 \\ = 1837.5[/tex]

We have the final answer as

Hope this helps you

Answer:

1mph

Explanation:

Answer:

W = 1526.43 J

Explanation:

Given that,

Force acting on a heavy crate, F = 325 N

The rope will make 29.0° angle with the horizontal

The distance covered by the crate, d = 5.37 m

We need to find the work done by the crate. The work done by an object is given by :

[tex]W=Fd\cos\theta\\\\=325 \times 5.37\times \cos29\\\\=1526.43\ J[/tex]

So, the required work done is 1526.43 J.

Answer :

556.59 m/s.

Explanation:

Given that,

An airplane is traveling at an altitude of 15,490 meters.

A  box of supplies is dropped from its cargo hold. We need to find the velocity of cargo when it hits the ground.

The initial velocity of the box is 0 as it as at rest. Let v is the velocity of cargo when it hits the ground. We can find it using third equation of motion as follows :

[tex]v^2-u^2=2as[/tex]

Put u = 0 and a = g

[tex]v^2=2gs\\\\v=\sqrt{2gs} \\\\v=\sqrt{2\times 10\times 15490 } \\\\v=556.59\ m/s[/tex]

So, when it hits the ground its velocity is 556.59 m/s.

Answer: 5N

Explanation:

Horizontal component is the force that is applied as a result of the diagonal application of force.

here in this case,

given diagonal force =10N.

angle= 30°

horizontal component is found using trigonometry..

so,

A vector of magnitude 10 N is provided.

It is at an angle of 30° to the + x axis.

To find:

The components along the x and y axis.

Calculation:

Along x axis:

F(x) = F cos(θ)

=> F(x) = 10 × cos(30)

=> F(x) = 10 (√3/2) = 5√3N

Along y axis:

F(y) = F sin(θ)

=> F(y) = 10 sin(30°)

=> F(y) = 10 × ½

=> F(y) = 5 N.

Additional information:

1. A vector is a quantity that can be defined with both magnitude and direction.

2. Since force is a vector, we are able to break it down into components along chosen axis.