Which force below acts at 90 degrees and is applied by a surface/wall to an object.

Interference is the ___________ of two or more waves.

Leokris [45]

Explanation:

\

its the 1 one

3 0

4 years ago

Read 2 more answers

Which of the following can lower the activation energy of a system?

exis [7]

Catalysts
a catalyst is something added to a reaction that speeds it up (or lowers the activation energy)

increasing the temp would speed up the whole reaction but not lower the activation energy
so B.

8 0

3 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

3 years ago

A campus bird spots a member of an opposing football team in an amusement park. The football player is on a ride where he goes a

kenny6666 [7]

Answer:

No..

Explanation:

As the bird releases the drop there is no internal force which will drive it into circular path but it will fall on tangent of the arc at the point of release because it has a tangential velocity same as bird. Path will be parabola in vertical plane.

As the person is on circular arc constantly moving it will never meet that drop.

6 0

4 years ago

Rocks A and B are located at the same height on top of a hill. The mass of rock A is twice the mass of rock B. How does the pote

Ronch [10]

Potential energy is defined by formula

$U = mgh$