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4 years ago

True or False?

Physics

1 answer:

DedPeter [7]4 years ago

8 0

Answer:

False. the system does not complete the circle movement

Explanation:

For this exercise, we must find the rope tension at the highest point of the path,

-T - W = m a

The acceleration is centripetal

a = v² / R

T = ma - mg

T = m (v² / R - g)

The minimum tension that the rope can have is zero (T = 0)

v² / R - g = 0

v = √ g R

Let's find out what this minimum speed is

v = √ 9.8 1

v = 3.13 m / s

We see that the speed of the body is less than this, so the system does not complete the movement.

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A man is flying in a hot-air balloon in a straight line at a constant rate of 5 feet per second, while keeping it at a constant

icang [17]

Answer:

$x = 220.85 ft$

Explanation:

Let at any moment of time the friend's car is at some horizontal distance "x" from the position of balloon.

Now if the altitude of the balloon is fixed and it is at height "h"

so here we will have

$tan \theta = \frac{h}{x}$

now we know that

initially the angle of the friend's car is 35 degree

so the horizontal distance will be

$x_1 = h cot35$

similarly if the angle after passing the car position is 36 degree

then we have

$x_2 = h cot36$

now the speed of the balloon is constant

so we have

$v = \frac{x_1 + x_2}{\Delta t}$

$5 ft/s = \frac{h cot35 + h cot36}{90 s}$

$5 ft/s = \frac{2.8h}{90}$

$h = 160.45 ft$

so the final position of friend when the angle is 36 degree

$x = \frac{h}{tan36}$

$x = \frac{160.45}{tan36}$

$x = 220.85 ft$

4 0

3 years ago

What is the magnitude of a point charge in coulombs whose electric field 58 cm away has the magnitude 2.8 N/C?

Yuliya22 [10]

Answer:

q = 1.05 × 10^-10 C

Explanation:

E = 2.8 N/C

r = 58cm = 0.58m

k = 9×10^9

q = ?

E = f/q

E = kq/r²

q = E*r²/k

q = (2.8×0.58²)÷9×10^9

q = 1.05 × 10^-10 C

8 0

3 years ago

A 0.280-kg volleyball approaches a player horizontally with a speed of 15.0 m/s. The player strikes the ball with her fist and c

Genrish500 [490]

Answer:

Impulse = 10.36 kg m/s

average force = 172.667 N

Explanation:

given data

mass = 0.280 kg

speed = 15.0 m/s

speed = 22.0 m/s

to find out

impulse and magnitude of the average force

solution

we know that Impulse is change in momentum that is

initial momentum = mass × speed ..........1

initial momentum = 0.28 × (15)

initial momentum = 4.2 kg m/s

Final momentum = mass × speed ..........2

Final momentum = 0.28 × (-22)

Final momentum = -6.16 kg m/s

so now we get Impulse that is

Impulse = 4.2 - (-6.16)

Impulse = 10.36 kg m/s

and

average force will be

average force = impulse ÷ time

average force = $\frac{10.36}{0.060}$

average force = 172.667 N

6 0

3 years ago

Suppose a small quantity of radon gas, which has a half-life of 3.8 days, is accidentally released into the air in a laboratory.

Daniel [21]

Answer:

1 day

Explanation:

Let the safe level = x

The current level = x + 0.2x = 1.2 x

Thus,

Half life = 3.8 days

$t_{1/2}=\frac {ln\ 2}{k}$

Where, k is rate constant

So,

$k=\frac {ln\ 2}{t_{1/2}}$

$k=\frac {ln\ 2}{3.8}\ days^{-1}$

The rate constant, k = 0.1824 days⁻¹

Using integrated rate law for first order kinetics as:

$[A_t]=[A_0]e^{-kt}$

Where,

$[A_t]$ is the concentration at time t

$[A_0]$ is the initial concentration

So,

$\frac {[A_t]}{[A_0]}$ = x / 1.2 x = 0.8333

t = ?

$\frac {[A_t]}{[A_0]}=e^{-k\times t}$

$0.8333=e^{-0.1824\times t}$

t ≅ 1 day

<u>Lab must be vacated in 1 day.</u>

4 0

3 years ago

What might happen if water molecules did not have a slight negative charge on one end and a slight positive charge on the other?

Katena32 [7]

Answer:

It would not be possible the cohesion among water molecules by the polar covalent bonding.

Well, to understand this in a better way, let's begin by explaining that water is special due to its properties, which makes this fluid useful for many purposes and for the existence of life.

In this sense, one of the main properties of water is cohesion (molecular cohesion), which is the attraction of molecules to others of the same type. So, water molecule ( $H_{2}O$ ) has 2 hydrogen atoms attached to 1 oxygen atom and can stick to itself through hydrogen bonds.

How is this possible?

By the polar covalent bonding, a process in which electrons are shared unequally between atoms, due to the unequal distribution of electrons between atoms of different elements. In other words: slightly positive and slightly negative charges appear in different parts of the molecule.

Now, it can be said that a water molecule has a negative side (oxygen) and a positive side (hydrogen). This is how the oxygen atom tends to monopolize more electrons and keeps them away from hydrogen. Thanks to this polarity, water molecules can stick together.

5 0

4 years ago