A model train moves 18.3m in 122s. What is the train's average speed?

explain which properties of metals make sterling silver the best material for you to create hammered earrings.

7nadin3 [17]

It is malleable

Explanation:

The property that makes metals such as sterling silver the best to create hammered earrings is their malleability.

All metals have a unique and fascinating property of being malleable. They can be carved into any of shape. When hammered they simply draw out and retain their long range ordering of their crystal lattice.

This is made possible by the presence of metallic bonding between the atoms.

The bulk of the physical properties of metals can be attributed the metallic bonds in them.
Metals have large sea of electrons in them.
In forming metallic bonds, there is an attraction between the positive nuclei of all the closely packed atoms in the lattice and the electron cloud jointly formed by all the atoms by loosing their outermost shell electrons.
Metals like silver have low ionization energy.
When they are hammered, they spread out the energy from the hammering.

learn more:

Metals brainly.com/question/2474874

#learnwithBrainly

8 0

2 years ago

An uncharged series RC circuit is to be connected across a battery. For each of the following changes, determine whether the tim

slavikrds [6]

a) Increase

b) Unchanged

c) Increase

Explanation:

a)

The charge on a capacitor charging in a RC circuit connected to a battery follows the exponential equation:

$Q(t)=Q_0 (1-e^{-\frac{t}{RC}})$

where

$Q_0 = CV$ is the final charge stored in the capacitor, where C is the capacitance and V is the voltage of the battery

t is the time

R is the resistance of the circuit

The capacitor reaches 90% of its final charge when

$Q(t)=0.90Q_0$

Substituting and re-arranging the equation, we find:

$0.90Q_0 = Q_0(1-e^{-\frac{t}{RC}})\\0.90=1-e^{-\frac{t}{RC}}\\e^{-\frac{t}{RC}}=0.10\\-\frac{t}{RC}=ln(0.10)\\t=-RCln(0.10)=2.30RC$

We see that if we double the RC constant, then $(RC)'=2(RC)$

So the time taken will double as well:

$t'=2.30(RC)'=2.30(2RC)=2(2.30RC)=2t$

So, the answer is "increase"

b)

In this second part, the battery voltage is doubled.

According to the equation written in part a),

$Q_0 =CV$

this means also that the final charge stored on the capacitor will also double.

However, the equation that gives us the time needed for the capacitor to reach 90% of its full charge is

$t=2.30 RC$

We see that this equation does not depend at all on the voltage of the battery.

Therefore, if the battery voltage is doubled, the final charge on the capacitor will double as well, but the time needed for the capacitor to reach 90% of its charge will not change.

So the correct answer is

"unchanged"

c)

In this case, a second resistor is added in series with the original resistor of the circuit.

We know that for two resistors in series, the total resistance of the circuit is given by the sum of the individual resistances:

$R=R_1+R_2$

Since each resistance is a positive value, this means that as we add new resistors, the total resistance of the circuit increases.

Therefore in this problem, if we add a resistor in series to the original circuit, this means that the total resistance of the circuit will increase.

The time taken for the capacitor to reach 90% of its final charge is still

$t=2.30 RC$

As we can see, this time is directly proportional to the resistance of the circuit, R: therefore, if we add a resistor in series, the resistance of the circuit will increase, and therefore this time will increase as well.

So the correct answer is

"increase"

8 0

2 years ago

A 5kg rock and a 10kg rock are dropped from a height of 10m?

fredd [130]

Look out below ! You should step nimbly to one side, to avoid being hit by one or the other of those hazardous weight objects when they arrive (at the same time).

5 0

2 years ago

d. The force is doubled and the object’s mass is halved? 18. ||| A man pulling an empty wagon causes it to accelerate at 1.4 m/s

Harrizon [31]

Answer:

$a' = 0.35 m/s^2$

Explanation:

Let say the empty wagon has mass "M"

now by newton's II Law we will have

$F = Ma$

now it is given that empty wagon is pulled with acceleration 1.4 m/s/s

now we will have

$F = 1.4 M$

now a child of mass three times the mass of wagon is sitting on the empty wagon

so here we have

$F = (M + 3M) a$

$1.4 M = 4M a'$

so we have

$a' = 0.35 m/s^2$

8 0

3 years ago

Which one of the following is a decomposition reaction?

BabaBlast [244]

You would know a decomposition reaction occurred if the reactants separated. For example from AB → A+B.

Now if you look at your options only 1 works out for that equation. Letter A.
From the compound K2CO3 it split up to K2O +CO2

It cannot be letter B because synthesis/combination occurred. The same goes for letter C. Letter D, single displacement occurred.

Again, the answer is A.

4 0

3 years ago