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2 years ago

25. How long does it take a child on a swing to complete one swing if her center of gravity is 4.00 m below the pivot?

Physics

1 answer:

Lina20 [59]2 years ago

4 0

Length=l=4m

$\\ \rm\rightarrowtail T=2\pi\sqrt{\dfrac{l}{g}}$

$\\ \rm\rightarrowtail T=2\pi\sqrt{\dfrac{4}{9.8}}$

$\\ \rm\rightarrowtail T=2\pi(0.63887)$

$\\ \rm\rightarrowtail T=1.27774\pi$

$\\ \rm\rightarrowtail T=4.012s$

You might be interested in

Doppler effect is caused by sound or light wave being pushed together and spread apart due to motion. True or False.

pychu [463]

Answer: false.

Explanation:

Doppler effect is caused to the relative motion of the source of light/sound with respect to the observer.

If the source is moving towards you, you will perceive the frequency to be larger (also called a blue shift), while if the wave is moving away, you will perceive the frequency to be smaller (also called a red shift).

Then the statement:

"Doppler effect is caused by sound or light wave being pushed together and spread apart due to motion."

Is false

3 0

2 years ago

2- A car on a straight highway goes in the positive direction for 8 km and then backs up for 3.6 km. What are the distance and d

IRISSAK [1]

Answer:

11.6km

4.4km in the negative direction

Explanation:

Distance is the total length of path covered and traveled by a body.

So, for this car on a straight line;

Total distance = 8km + 3.6km = 11.6km

Displacement is the distance traveled along a path and the direction it takes.

It is a vector quantity with magnitude and directional attributes.

For this journey;

Displacement = 8km - 3.6km = 4.4km in the negative direction.

4 0

2 years ago

Azurite is a mineral that contains 55.1% of copper. How many meter of copper wire with diameter of 0.0113 in can be produced fro

soldier1979 [14.2K]

Answer:

1402.73 m

Explanation:

Mass of Azurite=3.25 lb

Percent of copper in AZurite mineral=55.1%

Diameter of copper wire,d=0.0113 in

Radius of copper wire= $r=\frac{d}{2}=\frac{0.0113}{2}=0.00565 in=\frac{565}{100000}=\frac{565}{100}\times \frac{1}{1000}=5.65\times 10^{-3}in$

$\frac{1}{1000}=10^{-3}$

Density of copper= $\rho=8.96g/cm^3$

1 lb=454 g

3.25 lb= $3.25\times 454=1475.5 g$

Mass of Azurite= $1475.5 g$

Mass of copper= $\frac{55.1}{100}\times 1475.5=813 g$

Density= $\frac{Mass}{volume}$

Using the formula

$8.96=\frac{813}{volume\;of\;copper}$

Volume of copper wire= $\frac{813}{8.96}=90.7cm^3$

Radius of copper wire= $5.65\times 10^{-3}\times 2.54=14.35\times 10^{-3} cm$

1 in=2.54 cm

Volume of copper wire= $\pi r^2 h$

$\pi=3.14$

Using the formula

$90.7=3.14\times (14.35\times 10^{-3})^2\times h$

$h=\frac{90.7}{3.14\times (14.35\times 10^{-3})^2}$

$h=140273 cm$

1 m=100 cm

$h=\frac{140273}{100}=1402.73 m$

Hence, the length of copper wire required=1402.73 m

7 0

3 years ago

The speed of sound in air is 331 m/s. what is the plane's speed in terms of the speed of sound?

Zina [86]

<span>The initial speed, u of plane in terms of velocity of sound which may be taken as U
u=142/331=0.429*U
It crosses the sound barrier after says t seconds then we have 331-142=23.1*t or t is given 8.18 s exactly t=9/11s.
After 18 seconds the plane will traveling with velocity V
V=142+18*23.1=557.8 m/s==1.685*U</span>

5 0

2 years ago

Um corpo de massa 2,5kg é lançado verticalmente para cima. Se o sistema for considerado conservativo e no instante em que ele é

kvv77 [185]

Answer:

Energia mecânica = 300 Joules

Mechanical Energy = 300 Joules

Explanation:

given

m = 2.5kg

g=10m/s²

h=?

K.E = P.E

K.E = 150Joules

¹/₂mv² = m ×g ×h

150 J = 2.5 × 10 × h

h = 150/25

h= 6m

Mechanical energy = K.E + P.E

ME = 2 × 150 J

Mechanical Energy = 300Joules

dado

m = 2,5 kg

g = 10m / s²

h =?

K.E = P.E

K.E = 150Joules

¹ / ₂mv² = m × g × h

150 J = 2,5 × 10 × h

h = 150/25

h = 6m

Energia mecânica = K.E + P.E

ME = 2 × 150 J

Energia mecânica = 300Joules

7 0

3 years ago