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3 years ago

How to prove3 equations of motion graphically

1 answer:

6 0

Consider an object is moving with a uniform acceleration “a” along a straight line. The initial and final velocities of the object at time t = 0 and t = t are u and v respectively. During time t, let s be the total distance travelled by the object.

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Complete the following analogy. RADIO WAVES :LONGEST WAVELENGTH::_______: SHORTEST WAVELENGTH

forsale [732]

Gamma rays have the shortest wavelength.

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4 years ago

Allen Aby sets up an Atwood Machine and wants to find the acceleration and the tension in the string. Please help him. Two block

Vitek1552 [10]

<u>Answers:</u>

In order to solve this problem we will use Newton’s second Law, which is mathematically expressed after some simplifications as:

This can be read as: The Net Force $F$ of an object is equal to its mass $m$ multiplied by its acceleration $a$ .

We will also need to <u>draw the Free Body Diagram of each block</u> in order to know the direction of the acceleration in this system and find the Tension $T$ of the string (<u>See figure attached). </u>

We already know<u> $m_{2}$ is greater than $m_{1}$ </u>, this means the weight of the block 2 $P_{2}$ is greater than the weight of the block 1 $P_{1}$ ; therefore <u>the acceleration of the system will be in the direction of $P_{2}$ </u>, as shown in the figure attached.

We also know by the information given in the problem that <u>the pulley does not have friction and has negligible mass</u>, and <u>the string is massless</u>.

This means that the tension will be the same along the string regardless of the difference of mass of the blocks.

Now that we have the conditions clear, let’s begin with the calculations:

1) Firstly, we have to find the weight of each block, in order to verify that block 2 is heavier than block 1.

This is done using equation (1), where the force of the weight $P$ is calculated using the <u>acceleration of gravity</u> $g=9.8\frac{m}{s^{2}}$ acting on the blocks:

<u>For block 1: </u>

$P_{1}=m_{1}g$ (3)

$P_{1}=1.5kg(9.8\frac{m}{s^{2}})$

<u>For block 2: </u>

$P_{2}=m_{2}g$ (5)

$P_{2}=2.4kg(9.8\frac{m}{s^{2}})$

Then, we are going to <u>find the acceleration $a$ of the whole system: </u>

$F_{r}=P_{1}+P_{2}$ (7)

Where the Resulting Force $F_{r}$ is equal to the sum of the weights $P_{1}$ and $P_{2}$ .

In the figure attached, note that $P_{1}$ is in opposite direction to the acceleration $a$ , this means it must <u>have a negative sing</u>; while $P_{2}$ is in the same direction of $a$ .

Here we only have to isolate $a$ from equation (8) and substitute the values according to the conditions of the system:

$-14.7N+23.52N=(1.5kg+2.4kg)a$

$8.82N=(3.9kg)a$

Then:

$a=\frac{8.82N }{3.9kg}$

<h2> $a=2.26\frac{m}{ s^{2}}$ </h2><h2>This is the acceleration of the system. </h2>

2) For the second part of the problem, we have to find the tension $T$ of the string.

We can choose either the Free Body Diagram of block A or block B to make the calculations, <u>the result will be the same</u>.

Let’s prove it:

For $m_{1}$

we see in the free body diagram that the <u>acceleration is in the same direction of the tension of the string</u>, so:

$F_{r}=T-P_{1}$ (9)

$T-P_{1}=m_{1}a$ (10)

$T-14.7N=(1.5kg)( 2.26\frac{m}{ s^{2}})$

Then;

<h2> $T=18.09N$ This is the tension of the string </h2><h2> </h2>

For $m_{2}$

we see in the free body diagram that the acceleration is in opposite direction of the tension of the string and must <u>have a negative sign,</u> so:

$F_{r}=T-P_{2}$ (9)

$T-P_{2}=m_{2}a$ (10)

$T-23.52N=(2.4kg)(-2.26\frac{m}{ s^{2}})$

Then;

<h2> $T=18.09N$ This is the same tension of the string </h2>

6 0

3 years ago

You name binary ionic compounds by naming the first element or the ___ first,

Nuetrik [128]

Answer:

cation, anion

Explanation:

Binary Ionic Compounds- Binary means 2, ionic relates to charges. Therefore binary ionic compounds have TWO elements, with charges that cancel eachother out. The cation (or positive charge) goes before the anion (or negative charge)

example:

NaCl

Na^+1

Cl^-1

Sodium Chloride

6 0

4 years ago

Examples of Cardiovascular Endurance ( check all that apply)

sveta [45]

Answer:

Cardiorespiratory endurance is the level at which your heart, lungs, and muscles work together when you're exercising for an extended period of time.

...

Other activities
running or jogging.
swimming.
cycling.
dancing.
boxing.
aerobics or similar activities.
any active sport.

7 0

3 years ago

A Carnot heat engine has an efficiency of 0.200. If it operates between a deep lake with a constant temperature of 293.0 K and a

Dimas [21]

Answer:

366 K

Explanation:

T₀ = Constant Temperature of deep lake = 293.0 K

T = Temperature of hot reservoir connected to carnot engine = ?

η = Efficiency of Carnot engine during the operation

Efficiency of Carnot engine is given as

$\eta = 1-\frac{T_{o}}{T}$

Inserting the values

$0.200 = 1-\frac{293.0}{T}$

T = 366 K

3 0

4 years ago