What happens to the magnetic force as the distance between two magnetic poles decreases

Sort the questions based on whether they are better answered by an observational study or a controlled experiment.

Zepler [3.9K]

Answer:

Following questions are better answered by observational study:

- How does the daytime temperature affect the formation of dew at night?

- How effective is a new toothpaste in reducing cavities?

Following questions are better answered by controlled experiment:

- Which is a better absorber of heat, an object painted black or the same object painted white?

- Why does a rolling ball slow down as it moves?

- Can plants prepare food even in artificial light?

Explanation:

An observational study is one in which the researcher doesn't manipulate anything.

In a controlled experiment, the researcher manipulate the outcome of the experiment and controls the factors that might affect the experiment to see different results in different conditions.

So, for questions over which research do not have any control, mostly natural processes, observational study is a better option.

However, to check why a rolling ball slow down, controlled experiments are done to find out all the factors.

Plants placed in artificial light is also an controlled experiment as the researcher will himself place the plants in artificial light and keep them away from natural light.

Similarly, to check if color of the object affects the amount of heat absorbed by that object, a controlled experiment must be performed. Same object should be painted white and observed and then painted black and observed.

7 0

3 years ago

A tennis player tosses a tennis ball straight up and then catches it after 2.00 s at the same height as the point of release. (a

Readme [11.4K]

Answer:

Part a)

a = -9.81 m/s/s

Part b)

v = 0

Part c)

v = 9.81 m/s

Part d)

$H = 4.905 m$

Explanation:

Part a)

During the motion of ball it will have only gravitational force on the ball

so here the acceleration of the ball is only due to gravity

so it is given as

$a = g = 9.81 m/s^2$

Part b)

As we know that ball is moving against the gravity

so here the velocity of ball will keep on decreasing as the ball moves upwards

so at the highest point of the motion of the ball the speed of ball reduce to zero

$v_f = 0$

Part c)

We know that the total time taken by the ball to come back to the initial position is T = 2 s

so in this time displacement of the ball will be zero

$\Delta y = 0 = v_y t + \frac{1}{2} at^2$

$0 = v_y (2) - \frac{1}{2}(9.81)(2^2)$

$v_y = 9.81 m/s$

Part d)

at the maximum height position we know that the final speed will be zero

so we will have

$v_f^2 - v_i^2 = 2 a d$

here we have

$0 - (9.81^2) = 2(-9.81)H$

$H = 4.905 m$

4 0

3 years ago

I don’t understand can someone break it down for me

Westkost [7]

Answer:

a = (v² – v₀²)/ 2(s – s₀)

Explanation:

v² = v₀² + 2a (s – s₀)

We can make 'a' the subject of the above expression as follow:

v² = v₀² + 2a (s – s₀)

Subtract v₀² from both side

v² – v₀² = v₀² + 2a (s – s₀) – v₀²

v² – v₀² = v₀² – v₀² + 2a (s – s₀)

v² – v₀² = 2a (s – s₀)

Divide both side by (s – s₀)

(v² – v₀²)/ (s – s₀) = 2a

Divide both side by 2

(v² – v₀²)/ (s – s₀) ÷ 2 = a

(v² – v₀²)/ (s – s₀) × 1/2 = a

(v² – v₀²)/ 2(s – s₀) = a

a = (v² – v₀²)/ 2(s – s₀)

6 0

3 years ago

Which term defines the energy of motion?

damaskus [11]

Its (a) and(a)for the other ? and the last one is (d)

3 0

3 years ago

If you are swimming upstream (i.e., against the current), at what speed does your friend on the shore see you moving?

Alex777 [14]

Could be very slow since they’re basically going against the current which is hard so will be going slow

7 0

4 years ago