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3 years ago

An object moving with a constant

Physics

2 answers:

mixer [17]3 years ago

6 0

Answer:

Formula = m/s

Explanation:

The answer is 10 m / 5 seconds = 2 meters distance

The answer is 20 m / 5 seconds = 4 meters distance

jeka57 [31]3 years ago

5 0

Answer:

Acceleration:

${ \tt{a = \frac{v - u}{t} }} \\ { \tt{a = \frac{20 - 10}{5} }} \\ { \tt{a = 2 \: m {s}^{ - 2} }}$

From third equation:

${ \bf{ {v}^{2} = {u}^{2} + 2as}} \\ { \tt{s = \frac{ {20}^{2} - {10}^{2} }{2 \times 2} }} \\ = { \tt{s = 75 \: m}}$

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A Carnot engine's operating temperatures are 240 ∘C and 20 ∘C. The engine's power output is 910 W . Part A Calculate the rate of

scoray [572]

Answer:1200

Explanation:

Given data

Upper Temprature $\left ( T_H\right )=240^{\circ}\approx 513$

Lower Temprature $\left ( T_L\right )=20^{\circ}\approx 293$

Engine power ouput $\left ( W\right )=910 W$

Efficiency of carnot cycle is given by

$\eta =1-\frac{T_L}{T_H}$

$\eta =\frac{W_s}{Q_s}$

$1-\frac{293}{513}=\frac{910}{Q_s}$

$Q_s=2121.954 W$

$Q_r=1211.954 W$

rounding off to two significant figures

$Q_r=1200 W$

5 0

3 years ago

In Lesson 20, a magnesium strip was used to ignite the thermite reaction. When magnesium is placed in a flame from a small blow

nadezda [96]

Answer:

2 electrons will be needed by unbound oxygen in order to fill its 2nd shell.

Explanation:

The chemical reaction between magnesium and oxygen gives magnesium oxide as a product.The reaction is chemically represented as:

$2Mg(s)+O_2(g)\rightarrow 2MgO(s)$

Magnesium is a metal of group-2 with 2 valence electrons.It has atomic number of 12.

$[Mg]=1s^22s^22p^63s^2$

In order to attain noble gas configuration it will loose two electrons.

$[Mg]^{2+}=1s^22s^22p^6$

$Mg\rightarrow Mg^{2+}+2e^-$ ...[1]

Oxygen is a non metal of group-16 with 6 valence electrons..It has atomic number of 8.

$[O]=1s^22s^22p^4$

In order to attain noble gas configuration it will gain two electrons.

$[O]^{2-}=1s^22s^22p^6$

$O+2e^-\rightarrow O^{2-}$ ..[2]

2 electrons will be needed by unbound oxygen in order to fill its 2nd shell.

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4 years ago

A 50.0 N box sliding on a rough horizontal floor, and the only horizontal force acting on it is friction. You observe that at on

Vikki [24]

Answer:

-4.0 N

Explanation:

Since the force of friction is the only force acting on the box, according to Newton's second law its magnitude must be equal to the product between mass (m) and acceleration (a):

$F_f = ma$ (1)

We can find the mass of the box from its weight: in fact, since the weight is W = 50.0 N, its mass will be

$m=\frac{W}{g}=\frac{50.0 N}{9.8 m/s^2}=5.1 kg$

And we can fidn the acceleration by using the formula:

$a=\frac{v-u}{t}$

where

v = 0 is the final velocity

u = 1.75 m/s is the initial velocity

t = 2.25 s is the time the box needs to stop

Substituting, we find

$a=\frac{0-1.75 m/s}{2.25 s}=-0.78 m/s^2$

(the acceleration is negative since it is opposite to the motion, so it is a deceleration)

Therefore, substituting into eq.(1) we find the force of friction:

$F_f = (5.1 kg)(-0.78 m/s^2)=-4.0 N$

Where the negative sign means the direction of the force is opposite to the motion of the box.

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3 years ago

How do protons, neutrons and electrons determine the properties of the atoms??? HELP! NEED SCIENCE HELP FAST!!!!

Roman55 [17]

The number of protons determines the element. Many elements also have many isotopes. Such as carbon-14 Carbon-12 and carbon-10.

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3 years ago

A uniform-density sphere whose mass is 13 kg and radius is 0.3 m

geniusboy [140]

What are you trying to find?

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3 years ago