PLEASE PLEASE HELP<br> (Picture)

What is the frequency of a wave that has a period of vibration of 2 seconds?

34kurt

Answer:

The answer is 0.5 Hz

Explanation:

Its pretty easy to get the answer. One hertz (Hz) is equal to one cycle or period per second. So, just divide the period by the number of seconds.

1 period/2 secs = 1/2 Hz or 0.5 Hz

7 0

3 years ago

A 26 foot ladder is lowered down a vertical wall at a rate of 3 feet per minute. The base of the ladder is sliding away from the

lakkis [162]

Answer:

(i) 7.2 feet per minute.

(ii) No, the rate would be different.

(iii) The rate would be always positive.

(iv) the resultant change would be constant.

(v) 0 feet per min

Explanation:

Let the length of ladder is l, x be the height of the top of the ladder from the ground and y be the length of the bottom of the ladder from the wall,

By making the diagram of this situation,

Applying Pythagoras theorem,

$l^2 = x^2 + y^2-----(1)$

Differentiating with respect to t ( time ),

$0=2x\frac{dx}{dt} + 2y\frac{dy}{dt}$ ( l = 26 feet = constant )

$\implies 2y\frac{dy}{dt} = -2x\frac{dx}{dt}$

$\implies \frac{dy}{dt}=-\frac{x}{y}\frac{dx}{dt}$

We have,

$y = 10, \frac{dx}{dt}= -3\text{ feet per min}$

$\frac{dy}{dt}=\frac{3x}{10}-----(X)$

(i) From equation (1),

$26^2 = x^2 + 10^2$

$676=x^2 + 100$

$576 = x^2$

$\implies x = 24\text{ feet}$

From equation (X),

$\frac{dy}{dt}=\frac{3\times 24}{10}=7.2\text{ feet per min}$

(ii) From equation (X),

$\frac{dy}{dt}\propto x$

Thus, for different value of x the value of $\frac{dy}{dt}$ would be different.

(iii) Since, distance = Positive number,

So, the value of y will always a positive number.

Thus, from equation (X),

The rate would always be a positive.

(iv) The length of the ladder is constant, so, the resultant change would be constant.

i.e. x = increases ⇒ y = decreases

y = decreases ⇒ y = increases

(v) if ladder hit the ground x = 0,

So, from equation (X),

$\frac{dy}{dt}=0\text{ feet per min}$

3 0

3 years ago

How long will the ball be in the air if the cliff is 120 m tall and the ball falls to the base of the cliff?

Readme [11.4K]

Answer:

Explanation:

4.95s≈5s

Use equation :

h=G*t²/2

h=120m ----hight of cliff

G=9.81m/s²

t=?

-----------------------

h=G*t²/2

120m=9.81m/s²*t²/2

240m=9.81m/s²*t²

t²=240m/ 9.81m/s²

t²=24.46s

t=√24.46s²

t=4.95 s≈5s

3 0

4 years ago

How long will it take to go 150km traveling at 50km/hr? step by step please

Zigmanuir [339]

To find out time, you put distance over speed. So you would have to put 150 over 50. You divide 150 by 50 and you would get 3. So your answer is 3 hours.

3 0

3 years ago

Explain ALL THREE of Newton’s Laws in your own words.

Svet_ta [14]

Explanation:

(1) Every object moves in a straight line unless acted upon by a force. (2) The acceleration of an object is directly proportional to the net force exerted and inversely proportional to the object's mass. (3) For every action, there is an equal and opposite reaction.

5 0

3 years ago

PLEASE PLEASE HELP (Picture)