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3 years ago

4.) An apartment building is on fire and a guy is trapped on the fire escape ladder. There is a

Physics

1 answer:

Tems11 [23]3 years ago

3 0

Answer:

5.3 m/s

Explanation:

First, find the time it takes for him to fall 7m.

y = y₀ + v₀ t + ½ at²

0 = 7 + (0) t + ½ (-9.8) t²

0 = 7 − 4.9 t²

t ≈ 1.20 s

Now find the velocity he needs to travel 6.3m in that time.

x = x₀ + v₀ t + ½ at²

6.3 = 0 + v₀ (1.20) + ½ (0) (1.20)²

v₀ ≈ 5.27 m/s

Rounded to two significant figures, the man must run with a speed of 5.3 m/s.

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A vector has an x-component of -26.5 and a y-component of 43 units. Find magnitude and direction of vector

tatiyna

Answer:

The vector has a magnitude of 33.86 units and a direction of 121.64°.

Explanation:

To find the magnitude, you use the Pitagorean theorem:

$||V|| = \sqrt{x^2 + y^2}= \sqrt{(-26.5)^2 + (43)^2} = 33.86 units$

In order to find the direction, you can use trigonometry. You have to keep in mind, that as the y component of the vector is positive and the x component is negative, the vector must have an angle between 90 and 180°, or in the second quadrant of the plane.:

$tan(\alpha) = \frac{y}{x} \\\alpha = tan^{-1}(\frac{43}{-26.5})= 180 - tan^{-1}(\frac{43}{26.5}) = 121.64$ ° or, 58.36° in the second quadrant

6 0

4 years ago

Two charges, - Q0 and - 4Q0 are a distance d apart. These two charges are free to move but do not because there is a third charg

TEA [102]

To solve this problem we will use the equilibrium conditions in the Electrostatic Forces. In turn, we will use the concept formulated from Coulomb's laws to determine the intensity of the Forces and make the respective considerations.

Our values for the two charges are:

$q_1 = -Q_0$

$q_2 = -4Q_0$

As a general consideration we will start by determining that they are at a unit distance (1) separated from each other. And considering that both are negative charges, they will be subjected to repulsive force. Said equilibrium compensation will be achieved only by placing a third force between the two.

Let the third charge be $q_3 = +Q$ is placed at a distance x from $q_1$

$F_{1,3} = \frac{k(-Q_0)(+Q)}{x^2}$

The force on $q_3$ due to $q_2$ is

$F_{2,3} = \frac{k(-4Q_0)(+Q)}{1-x^2}$

The condition of equilibrium is

$F_{1,3} = F_{2,3}$

$\frac{k(-Q_0)(+Q)}{x^2}= \frac{k(-4Q_0)(+Q)}{1-x^2}$

$\frac{1}{x^2} = \frac{4}{(1-x)^2}$

$x = 0.331$ from $q_1$

To find the magnitude of $q_3$ we use $F_{1,2} = F_{1,3}$

$\frac{k(-Q_0)(4Q_0)}{1^2}= \frac{k(-Q_0)(Q)}{0.331^2}$

$Q = 0.43Q_0$

The magnitude of the third charge must be 0.43 the first charge $Q_0$

3 0

3 years ago

A 210Ω resistor is connected in a circuit with a 110V battery. What total amount of charge passes through a point in the circuit

irina1246 [14]

Answer: 62.86 coulombs

Explanation:

Resistance (R) = 210Ω

Voltage of battery (V) = 110V

total amount of charge (Q) = ?

Time (T) = 2 minutes

The SI unit of time is seconds so convert 2 minutes to seconds

(If 1 minute = 60 seconds

2 minutes = 2 x 60 = 120 seconds)

To get the total charge, first get the current (I) flowing in the circuit by applying the formula V = IR

110V = I x 210Ω

I = 110V/210Ω

I = 0.524 Amps

Then, apply the formula

Charge = current x time

i.e Q = IT

Q = 0.524 Amps x 120 seconds

Q = 62.86 coulombs

Thus, 62.86 coulombs of charge passes through the circuit.

6 0

4 years ago

What does the law of conservation of energy state?

VikaD [51]

The total amount of energy remains constant in an isolated system. It implies that energy can neither be created nor destroyed, but can be change from one form to another.

6 0

3 years ago

One of the possible criteria of Schizophrenia is hallucinations.

Helen [10]

It is true but that’s not Physics

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2 years ago