# Showcase - Physics

### Author: Edu Plexor

Ant

 An ant is crawling along the edge of a round cup at a constant speed. Its movement is observed when it crawled half of the way.   You can make singlechoice questions, where you click on the right answer!

Correct!

Wrong answer. The speed doesn't change with time. The real solution is

Arrange

Properly arrange the labels.

 $^{5}He$ $^{3}T$ $^{5}Li$ $^{2}D$

Matching can also be made with images.

Correct.

Again you are wrong. Proper name:

 $^{5}He$ $^{3}T$ $^{5}Li$ $^{2}D$

You are wrong.

Alpha particle

 Figure shows an alpha particle. Alpha particle is a helium nucleus. How many protons has an alpha particle? How many neutrons has an alpha particle? Check

You can make questions with numerical answers, where the user writes the right anwser in the box provided.

Correct!

The anwser is still not correct. Number of protons is 2 and the number of neutrons is also 2.

The answer is wrong. Try again.

Shape of the jet

 A water jet maintains a constant the flow rate. Select the equation that describes the conservation of the flow rate. Points 1 and 2 are marked on the image. $S_1 v_1 = S_2 v_2$ $p_1 V_1 = p_2 V_2$ $\rho g h_1 = \rho g h_2$ $v_1 = v_2$

The answer is incorrect. The flow is defined as:

.

Again, you did not answer correctly.

We know: $v_1 S_1 = v_2 S_2$. Connection $\Phi = S v$ can be derived from the definition of the flow

Speed of the car

Calculate the speed of the car. In calculating the acceleration, take g to be $9,81$ m/s$^2$.

 $F_c = \frac{mv^2}{r}$ $F_c = mg \tan \varphi$

$v_1 =$ m/s

Hitrost izračunamo tako, da zapišemo $2.$ Newtonov zakon za kroženje.
$F = ma_r$
$mg \tan \varphi = m \frac{v^2}{r}$
$v = \sqrt{rg} \tan \varphi$

You can add images to make the exercise clearer.

Radius: $r=$ m.

Angle: $\varphi =$ $^o$.

Red circle

Watch the red circle from beginning to end movement. Which statement about the cycle is correct?

The movement from the initial position is

The answer is correct. The initial position is $2$ and the final is $-1$.

The initial position is $2$ and the final is $-1$. Move the circle is $-3$.

Circuit

Take a good look at the circuit in the photo. Predict how the lamps A, B and C will light, after connecting the upper left crocodile at the free connector of the left battery. The resistance of the wires is negligible.

Select from the following numbers in the table:
$2$-bulb is strongly lit,
$1$-bulb is weakly lit,
$0$-bulb is not lit.

 A 0 1 2 B 0 1 2 C 0 1 2 D 0 1 2

Another option for the questions are the ones, where the possible answers are given in a drop-down menu.

The answer is incorrect. Hint: The circuit is a seguence binding together two light bulbs and circuits in which the remaining bulbs are connected in parallel.

The circuit is a sequence binding bulbs A and B, and the circuit in which C and D are bound in parallel. Therefore, through the A and B running full flow through C and D through only half the flow that is driven by batteries.

Ball in the water

The image below shows a submerged ball of oak wood. Images are marked with A, B and C.

Link each image with the appropriate name of the liquid.

 A B C
A
B
C
WATER
LINSEED OIL
GLYCERIN

Well done!

Hmmm... think, when the body better swim?

# Table densities

1. Solids2. Fluid2. Fluid
a) Liquidb) Gases
 substance density $[\frac{kg}{dm^3}]$ cobalt $8.60$ glass $3.00$ limestone $2.60$ oak wood $0.90$ pine wood $0.50$ cork $0.25$
 substance density $[\frac{kg}{dm^3}]$ glycerin $1.26$ water $1.00$ linseed oil $0.92$ benzol $0.88$ naphtha $0.80$ gasoline $0.71$
 substance density $[\frac{kg}{dm^3}]$ air $1.29*10^{-3}$ ammonia $0.77*10^{-3}$ helium $0.17*10^{-3}$

Car making a turn

Using tools over the images you can create many dynamical exercises.

We make a turn with a car, as shown in the image. With the help of the tools on the image, measure the radius of the loop.

$R =$ m

While searching for the radius of the loop it is cruical to understand, that the loop is just a part of the circumference.

We expect some users to have issues with determining where is the radius of the circumference. Therefore we should help ourselves with the image of the circumference wirh the radius drawn in it. We take radius with values between 42 and 52 as correct.

Excellent! We can continue.

The result of the measurement is false. Correct result is $47$ m $\pm$ $5$ m.

Angle of a leaning object

Photo shows a pendant in a car during driving in the right corner. From the picture define angle, for which is the pendant away from the vertical.

$\phi =$ $^{o}$

We take for correct the angles between $19$ o and $23$ o.

Excellent! We can continue.

Result of the measurement is incorrect. Try again.

Result of the measurement is incorrect. The correct answer is $21^{o}$ $\pm 2^{o}$.

Star card

Which constellation will ride exactly in the East on 5th of December at $19.00$?

With star map you can cover many topics in astronomy.

Excellent, you are doing very well.

It's true.

The answer is not correct. Try again!

On 5th of December at 19:00, exactly in the East, there will be rise of the Orion constellation.

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