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sergij07 [2.7K]

2 years ago

13

If a golf ball is dropped from the thirteenth floor of a building, ignoring air resistance, after falling for 7.00 seconds the s

peed of the ball will be?

1 answer:

PIT_PIT [208]2 years ago

6 0

Explanation:

We know that

V = U + at

Here, u is 0 and a is 9.8 which is acceleration due to gravity.

Thus,

V = 9.8 *7

V = 68.6 m/s

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A 100 Ω resistor is connected in series with a 47 µF capacitor and a source whose maximum voltage is 5 V, operating at 100.0 Hz.

Pani-rosa [81]

Answer:

$X_c=-33.86275385\Omega$

$|Z|=105.5778675\Omega$

$I=0.04735841062A$

$\phi=20.78612878\°$

Explanation:

The electrical reactance is defined as:

$X_c=-\frac{1}{2\pi fC}$

Where:

$f=Frequency\\C=Capacitance$

So, replacing the data provided by the problem:

$X_c=\frac{1}{2\pi *100*(47*10^{-6} )} =-33.86275385\Omega$

Now, the impedance can be calculated as:

$Z=R+jX_c$

Where:

$R=Resistance\\X_c= Capacitive\hspace{3}reactance$

Replacing the data:

$Z=100-j33.86275385$

In order to find the magnitude of the impedance we can use the next equation:

$|Z|=\sqrt{(R^2)+(X_c^2)}=\sqrt{(100)^2+(-33.86275385)^2} =105.5778675\Omega$

We can use Ohm's law to find the current:

$V=I*Z\\I=\frac{V}{Z}$

Therefore the current is:

$I=\frac{5}{100-j33.86275385}=0.04485638113+0.01518960593j$

And its magnitude is:

$|I|=\sqrt{(0.04485638113)^2+(0.01518960593)^2} =0.04735841062\Omega$

Finally the phase angle of the current is given by:

$\phi=arctan(\frac{0.01518960593}{0.04485638113})=20.78612878\°$

5 0

2 years ago

A warehouse worker is pushing a 90.0-kg crate with a horizontal force of 282 N at a speed of v = 0.850 m/s across the warehouse

Elanso [62]

Answer:

$v_{f} = 0.51 \frac{m}{s}$

Explanation:

We apply Newton's second law at the crate :

∑F = m*a (Formula 1)

∑F : algebraic sum of the forces in Newton (N)

m : mass in kilograms (kg)

a : acceleration in meters over second square (m/s²)

Data:

m=90kg : crate mass

F= 282 N

μk =0.351 :coefficient of kinetic friction

g = 9.8 m/s² : acceleration due to gravity

Crate weight (W)

W= m*g

W= 90kg*9.8 m/s²

W= 882 N

Friction force : Ff

Ff= μk*N Formula (2)

μk: coefficient of kinetic friction

N : Normal force (N)

Problem development

We apply the formula (1)

∑Fy = m*ay , ay=0

N-W = 0

N = W

N = 882 N

We replace the data in the formula (2)

Ff= μk*N = 0.351* 882 N

Ff= 309.58 N

We apply the formula (1) in x direction:

∑Fx = m*ax , ax=0

282 N - 309.58 N = 90*a

a= (282 N - 309.58 N ) / (90)

a= - 0.306 m/s²

Kinematics of the crate

Because the crate moves with uniformly accelerated movement we apply the following formula :

vf²=v₀²+2*a*d Formula (3)

Where:

d:displacement in meters (m)

v₀: initial speed in m/s

vf: final speed in m/s

a: acceleration in m/s²

Data

v₀ = 0.850 m/s

d = 0.75 m

a= - 0.306 m/s²

We replace the data in the formula (3)

vf²=(0.850)²+(2)( - 0.306 )(0.75 )

$v_{f} = \sqrt{(0.850)^{2} +(2)( - 0.306 )(0.75 )}$

$v_{f} = 0.51 \frac{m}{s}$

8 0

3 years ago

How do you calculate the magnitude of the resultant force of two

zlopas [31]

Answer:

Two forces that act in opposite directions produce a resultant force that is smaller than either individual force. To find the resultant force subtract the magnitude of the smaller force from the magnitude of the larger force. The direction of the resultant force is in the same direction as the larger force.

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2 years ago

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Why cant soy sauce freeze

juin [17]

The salt content in soy

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Where would a car traveling on a roller coaster have the most kinetic energy ? and why?

goldenfox [79]

Answer:

As the car travels up the coaster it is gaining potential energy.

Explanation:

Because It has the greatest in amount of potential energy at the top of the coaster. when the car travels down the roller coaster it obtains speed and kinetic energy.

4 0

2 years ago

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