A wave has a period of 4 seconds. What is its frequency?

Art [367]

I believe yes they do hope this helps

6 0

3 years ago

A ball is whirled on the end of a string in a horizontal circle of radius R at constant speed v. Which way(s) can increase the c

Charra [1.4K]

Explanation:

When an object moves in a circular path, due to the change in its velocity, the object possess centripetal acceleration. The formula for the centripetal acceleration is given by :

$a=\dfrac{v^2}{R}$

Where

v is the speed of the object

R is the radius of the circle path

Option (1) : Keeping the speed fixed and decreasing the radius by a factor of 9

$a=\dfrac{v^2}{R/9}$

$a=\dfrac{9v^2}{R}$

The centripetal acceleration of the ball by a factor of 9.

Option (2) : Keeping the radius fixed and increasing the speed by a factor of 3

$a=\dfrac{(3v)^2}{R}$

$a=\dfrac{9v^2}{R}$

The centripetal acceleration increases by a factor of 9.

Option (3) : Decreasing both the radius and the speed by a factor of 9.

$a=\dfrac{(v/9)^2}{R/9}$

$a=\dfrac{(v)^2}{9R}$

The centripetal acceleration decreases by a factor of 9.

Option (4) : Keeping the radius fixed and increasing the speed by a factor of 9

$a=\dfrac{(3v)^2}{R}$

$a=\dfrac{9v^2}{R}$

The centripetal acceleration increases by a factor of 9.

Option (5) : Increasing both the radius and the speed by a factor of 9

$a=\dfrac{(9v)^2}{9R}$

$a=\dfrac{9v^2}{R}$

The centripetal acceleration increases by a factor of 9.

Option (6) : Keeping the speed fixed and increasing the radius by a factor of 9

$a=\dfrac{(v)^2}{9R}$

$a=\dfrac{9v^2}{R}$

The centripetal acceleration increases by a factor of 9.

So, as the radius of the circle decreases, its centripetal acceleration increase. Also, if the speed of the object increases, its centripetal acceleration increase. Hence, this is the required solution.

4 0

3 years ago

You make tea with 0.50 kg of 85.0Â°C water and let it cool to room temperature 120.0Â°C2.

dedylja [7]

Answer:

Explanation:

a ) Entropy change dS = dQ/T

= mcdT /T

Integrating both sides

S₂ - S₁ = - mclnT₂ /T₁

= - .5 X 4200 ln (85+273) /( 20 + 273 )

.5 X 4200 ln 358/ 293

= - 417.6 J/K

Entropy change will be negative as heat is lost by the system .

b ) Sine there is no change in the temperature of air , This heat will enter air at temperature ( 20+ 273) K = 293 K

Heat entering air

= .5 x 4200 x 65

= 136500 J

Change in entropy

136500 / 293 ( room temperature is constant at 293k

= + 465.87 J/K

Entropy change will be positive as heat is gained by the system .

Total change in the entropy of the system (tea + air )

= +465.87 - 417.6

= 48.27 J/K

Entropy change will be negative as heat is lost by the system .

5 0

3 years ago

In the process of changing a flat tire, a motorist uses a hydraulic jack. She begins by applying a force of 48 N to the input pi

erik [133]

Answer:

Force that the output plunger applies to the car; F2 = 3888N

Explanation:

For a hydraulic device, the relationship between the force and the area using Pascal's principle is;

F1/A1 = F2/A2

Where;

F1 is force applied to the input piston

F2 is force that the output plunger applies to the car

A1 is Area of input piston

A2 is area of larger piston

We are given;

R2/R1 = 9

So,R2 = 9R1

F1 = 48N

Area of input piston;

A1 = π(R1)²

Area of output piston;

A2 = π(9R1)²

Since, (F1/A1) = (F2/A2)

Thus;

F1/(π(R1)²) = F2/(π(9R1)²)

If we simplify, π(R1)² will cancel out to give;

F1 = F2/9²

Thus;

F2 = 9² x F1

Plugging in 48N for F1, we have;

F2 = 9² x 48

F2 = 81 x 48

F2 = 3888N

8 0

3 years ago

As a pan is sitting on a stove it begins to heat up. Eventually it may get hot enough that it glows red, meaning it is radiating

saul85 [17]

Answer:
Your answer is B.!

When things in general get hotter, the atoms inside move faster and vise versa with cold.

(for example water); if you put water in a pot on a stove to boil, its gets so hot to where the atoms are moving really fast to get it to look like that.

Please mark brainiest! if this answer is wrong, (which I'm pretty sure it isn't) then pick D. :D

4 0

2 years ago