If the molecules in the desk in front of you are moving, then<br> why is the desk standing still?

A golf ball is struck with a five iron on level ground. it lands 100.0 m away 4.60 s later. what was the magnitude and direction

finlep [7]

consider the motion in x-direction

$v_{ox}$ = initial velocity in x-direction = ?

X = horizontal distance traveled = 100 m

$a_{x}$ = acceleration along x-direction = 0 m/s²

t = time of travel = 4.60 sec

Using the equation

X = $v_{ox}$ t + (0.5) $a_{x}$ t²

100 = $v_{ox}$ (4.60)

$v_{ox}$ = 21.7 m/s

consider the motion along y-direction

$v_{oy}$ = initial velocity in y-direction = ?

Y = vertical displacement = 0 m

$a_{y}$ = acceleration along x-direction = - 9.8 m/s²

t = time of travel = 4.60 sec

Using the equation

Y = $v_{oy}$ t + (0.5) $a_{y}$ t²

0 = $v_{oy}$ (4.60) + (0.5) (- 9.8) (4.60)²

$v_{oy}$ = 22.54 m/s

initial velocity is given as

$v_{o}$ = sqrt(( $v_{ox}$ )² + ( $v_{oy}$ )²)

$v_{o}$ = sqrt((21.7)² + (22.54)²) = 31.3 m/s

direction: θ = tan⁻¹(22.54/21.7) = 46.12 deg

6 0

3 years ago

A sinusoidal wave traveling on a string has a period of 0.20 s, a wavelength of 32 cm, and an amplitude of 3 cm. The speed of th

Finger [1]

Answer:

$v = 1.6 \frac{m}{s} *\frac{100cm}{1m}= 160 \frac{cm}{s}$

Explanation:

If we have a periodic wave we need to satisfy the following basic relationship:

$v = \lambda f$

From the last formula we see that the velocity is proportional fo the frequency.

For this case we have the following info given by the problem:

$T= 0.2 s, \lambda =32 cm* \frac{1m}{100cm} =0.32 m, A= 3cm*\frac{1m}{100 cm}=0.03 m$

We know that the frequency is the reciprocal of the period so we have this formula:

$f = \frac{1}{T}$

And if we replace we got:

$f =\frac{1}{0.2 s}= 5Hz$

Now since we have the value for the wavelength we can find the velocity like this:

$v = 0.32 m * 5Hz = 1.6 \frac{m}{s}$

And if we convert this into cm/s we got:

$v = 1.6 \frac{m}{s} *\frac{100cm}{1m}= 160 \frac{cm}{s}$

6 0

3 years ago

How is sunlight different from light produced by a light bulb or by a fluorescent light bulb

Leona [35]

Sunlight emits more energy than artificial light. Sunlight is better and healthier than most artificial lights and helps plants to grow more.

4 0

3 years ago

What is the difference between charging by contact and charging by induction in terms of electron transfer.

Veronika [31]

Answer:

the main difference between charging by contact and charging by induction is that in the first case, the two objects are touching, while in the second case, the two objects do not touch

Explanation:

There are three methods of charging an object:

- Charging by friction: this is done by rubbing an object against another object. An example is when a plastic rod is rubbed with a wool cloth. When this is done, electrons are transferred from the wool to the rod, so both objects remain charged at the end of the process

- Charging by contact: this is done by putting in contact a charged object with a neutral, conducting object. In this case, the charges are transferred from the charged object to the neutral object; at the end of the process, the neutral object will also have a net electric charge, so it will be also charged.

- Charging by induction: in this case, we take a charged object, and a neutral object, and we place the two objects close to each other, but without touching. Let's assume that the charged object is negatively charged: in this case, the positive charges in the neutral object are attracted towards the negative charges of the charged object, while the negative charges of the neutral object are repelled away. As a result, the positive and negative charges in the neutral object split apart. If the object is connected to the ground, then negative charges move away, so the neutral object will remain positively charged.

Therefore, the main difference between charging by contact and charging by induction is that in the first case, the two objects are touching, while in the second case, the two objects do not touch.

5 0

3 years ago

A metal cylinder with a mass of 4.20 kg is attached to a spring and is able to oscillate horizontally with negligible friction.

kherson [118]

Answer:

a) k = 120 N / m

, b) f = 0.851 Hz

, c) v = 1,069 m / s

, d) x = 0

, e) a = 5.71 m / s²

, f) x = 0.200 m

, g) Em = 2.4 J

, h) v = -1.01 m / s

Explanation:

a) Hooke's law is

F = k x

k = F / x

k = 24.0 / 0.200

k = 120 N / m

b) the angular velocity of the simple harmonic movement is

w = √ k / m

w = √ (120 / 4.2)

w = 5,345 rad / s

Angular velocity and frequency are related.

w = 2π f

f = w / 2π

f = 5.345 / 2π

f = 0.851 Hz

c) the equation that describes the movement is

x = A cos (wt + Ф)

As the body is released without initial velocity, Ф = 0

x = 0.2 cos wt

Speed is

v = dx / dt

v = -A w sin wt

The speed is maximum for sin wt = ±1

v = A w

v = 0.200 5.345

v = 1,069 m / s

d) when the function sin wt = -1 the function cos wt = 0, whereby the position for maximum speed is

x = A cos wt = 0

x = 0

e) the acceleration is

a = d²x / dt² = dv / dt

a = - Aw² cos wt

The acceleration is maximum when cos wt = ± 1

a = A w²

a = 0.2 5.345

a = 5.71 m / s²

f) the position for this acceleration is

x = A cos wt

x = A

x = 0.200 m

g) Mechanical energy is

Em = ½ k A²

Em = ½ 120 0.2²

Em = 2.4 J

h) the position is

x = 1/3 A

Let's calculate the time to reach this point

x = A cos wt

1/3 A = A cos 5.345t

t = 1 / w cos⁻¹(1/3)

The angles are in radians

t = 1.23 / 5,345

t = 0.2301 s

Speed is

v = -A w sin wt

v = -0.2 5.345 sin (5.345 0.2301)

v = -1.01 m / s

i) acceleration

a = -A w² sin wt

a = - 0.2 5.345² cos (5.345 0.2301)

a = -1.91 m / s²

5 0

3 years ago

If the molecules in the desk in front of you are moving, then why is the desk standing still?