A baseball team is practicing throwing balls vertically upward to test their throwing arms. A player manages to throw a ball that reaches a maximum altitude of 10 m above the launch point, before falling back down. The acceleration due to gravity is 9.80 m/s 2 . (a) With what initial speed was the ball thrown? (b) How long did it take for the ball to reach its maximum altitude?

Answer : The incorrect option is (b) They can be reversed by physical changes.

Explanation :

Chemical change : It is a change where changes occurs in the chemical composition and thus resulting in the formation of new compound or substance. It is an irreversible reaction.

The indication of chemical changes are :

Formation of gas bubbles.

Formation of precipitate.

Change in color.

Change in temperature.

Change in volume.

Change in smell or taste.

Evolution of heat, light and sound.

Physical change : It is a change in which shape and size of a substance changes. In this there is no change in the chemical composition of the substance and no new substance is forming. It is a reversible reaction.

The indication of chemical changes are :

Change in shape.

Change in form.

Change in size.

Change in phase.

From the given options we conclude that the option (b) is incorrect option while all the options are correct for chemical changes.

Hence, the incorrect option is (b)

Answer:

mass of other skater is 31.3 kg

Explanation:

Here since we know that two skaters push each other so if we consider two skaters as system then there is no external force on the system.

hence we can say that momentum of the system is conserved

so here we have

[tex]P_i = P_f[/tex]

now we can say that initially both skaters are at rest so initial total momentum is ZERO for both

now we have

[tex]0 = m_1v_{1i} + m_2v_{2i}[/tex]

[tex]0 = 45(0.62) + m_2(-0.89)[/tex]

[tex]m_2 = 31.3 kg[/tex]

Based on the information given, the mass of the other skater will be 31.3 kg.

From the information given, ice skaters stand at rest in the center of an ice rink. when they push off against one another the 45-kg skater acquires a speed of 0.62 m/s and the speed of the other skater is 0.89 m/s.

Therefore, the mass of the skater will be:

0 = 45(0.62) + (-0.89)m

m = 31.3kg

In conclusion, the correct option is 31.3kg.

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The horizontal component of the projectile's acceleration is zero.

A projectile is an item on which gravity is the sole force operating. Projectiles come in a range of shapes and sizes.

A projectile is an item that is launched from its resting position. A projectile is an item that is hurled vertically upward.

A projectile's horizontal velocity is constant, which is downward. Each second, a projectile's vertical velocity varies by 9.8 meters per second.

A projectile's horizontal motion is independent of its vertical motion.

Hence the horizontal component of the projectile's acceleration is zero.

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The velocity of the car at s = 550 ft is 2,904,166.67 ft/s and the acceleration at s = 550 ft is 1512.5 ft/s^2.

The velocity of the car can be determined by finding the integral of the acceleration function with respect to time. In this case, the acceleration function is v' = 0.05t^2. Integrating this function gives the velocity function v = (0.05/3)t^3 + C, where C is the constant of integration. To find the value of C, we can use the fact that the car is originally at rest, so v(0) = 0. Plugging in the values, we get C = 0, so the velocity function is v = (0.05/3)t^3.

To find the magnitude of the velocity at t = 550 ft, we can plug in the value of t into the velocity function. So, v = (0.05/3)(550)^3 = 2,904,166.67 ft/s. Therefore, the magnitude of the velocity at s = 550 ft is 2,904,166.67 ft/s.

The acceleration can be determined by taking the derivative of the velocity function with respect to time. In this case, the velocity function is v = (0.05/3)t^3. Taking the derivative, we get a = (0.05)t^2. Plugging in the value of t = 550 ft, we get a = (0.05)(550)^2 = 1512.5 ft/s^2. Therefore, the magnitude of the acceleration at s = 550 ft is 1512.5 ft/s^2.

Final answer:

The force of attraction between cations and anions is electrostatic attraction, which is fundamental to the formation of ionic bonds. The strength of this force depends on the charges of the ions and the distance between them, with stronger forces resulting from higher charges or shorter distances. The arrangement of ions in a crystal structure and the Madelung constant also play roles in the bond strength.

Explanation:

The force of attraction between cations and anions is known as electrostatic attraction. This is the principle underlying ionic bonds, which form when electrons are transferred from one atom to another, leading to the creation of oppositely charged ions that are held together by this force. According to Coulomb's law, the strength of the electrostatic force between two ions is directly proportional to the product of their charges and inversely proportional to the square of the distance between them.

A cation with a greater positive charge will form a stronger bond than one with a lesser charge. Conversely, larger ions result in weaker bonds due to the increased distance between the electrons of one ion and the nucleus of the other. Additionally, the orientation of ions in a crystal lattice affects the attractive forces. Salts such as NaF and NaCl are classic examples, where ions arrange themselves in a way to maximize attractive interactions and minimize repulsive ones.

The Madelung constant also influences the bond strength and depends on the type of crystal structure. The potential energy of an ionic bond can be quantitatively expressed using the formula involving Avogadro's number, Madelung constant, ion charges, the charge of an electron, and the ion radius.

The energy of a photon with a frequency of 5.20 x 10^14 Hz is calculated using the equation E = hf, which results in an energy of 3.448 x 10^-19 joules.

To calculate the energy of a photon with a specific frequency, we use the following equation:

E = hf

Here, E represents the energy of the photon in joules, h is Planck's constant, and f is the frequency of the photon given in hertz (Hz). With the values provided in the question, we get:

E = (6.63 × 10^-34 J·s) × (5.20 × 10^14 Hz)

Calculating the above expression leads to:

E = 3.448 × 10^-19 joules

Therefore, the energy of the photon with a frequency of 5.20 × 10^14 hertz is 3.448 × 10^-19 joules.

Final answer:

To calculate the force a 40.0-kg gymnast must exert to decelerate at 7 times the acceleration due to gravity, we use Newton's second law (F = ma) and find that she must exert approximately 2746.8 N.

Explanation:

Calculating the Force Exerted by a Gymnast

When a 40.0-kg gymnast lands and decelerates, she must exert a force to counteract the force of deceleration. To calculate the force she must exert if her deceleration is 7.00 times the acceleration due to gravity, we use Newton's second law of motion, which can be expressed as F = ma, where F is the force, m is the mass of the object, and a is the acceleration. First, we note that the acceleration due to gravity (g) is approximately 9.81 m/s². The deceleration she experiences would thus be 7 times 9.81 m/s², or approximately 68.67 m/s².

To calculate the total force, we multiply the gymnast's mass by the deceleration:

Force exerted (F) = Mass (m) × Deceleration (a)

F = 40.0 kg × 68.67 m/s²

F = 2746.8 N

Therefore, the gymnast must exert a force of approximately 2746.8 N by pushing down on the mat to achieve this deceleration.

Answer:

21.7 seconds

Explanation:

The speedometer in a car does not measure velocity because velocity is a vector quantity, including both speed and direction, and the speedometer only provides information about speed (magnitude). So, the correct option is A, velocity is a vector quantity that includes both speed and direction.

Let's go into more detail:

Velocity:

- Velocity is a vector quantity that includes both speed and direction.

- Speed is the magnitude of velocity, representing how fast an object is moving.

- Direction is a crucial component of velocity; it indicates the path an object is taking.

Speed:

- Speed is a scalar quantity, representing only the magnitude of motion, or how fast an object is moving.

- It does not include information about the direction of motion.

Speedometer in a Car:

- The speedometer in a car measures the instantaneous speed of the vehicle.

- It provides information about how fast the car is moving at a given moment.

- However, the speedometer does not provide any information about the direction in which the car is moving.

- Since velocity includes both speed and direction, and the speedometer only measures speed, it does not directly measure velocity.

Correct Answer (A):

- The correct option is (A) because velocity is indeed a vector quantity, having both magnitude (speed) and direction.

- The speedometer, by measuring speed alone, does not account for the directional component of velocity.

Complete Question: The speedometer in a car does not measure the car's velocity because velocity is a

(A) vector quantity and has a direction associated with it

(B) vector quantity and does not have a direction associated with it

(C) scalar quantity and has a direction associated with it

(D) scalar quantity and does not have a direction associated with it

We are given the following values:

weight w = 240 lb = 1,067.52 N

energy E = 3,000 J

The formula for potential energy is:

E = w h

where h is the height the person has to climb, therefore:

h = 3000 / 1067.52

h = 2.81 m

Therefore he has to climb 2.81 meters

The initial height of the rock can be calculated using the principles of projectile motion. First, we find the time the rock was in the air by using the horizontal motion, and then apply this time to the vertical motion taking gravity into account.

Using the principles of projectile motion, the objective is to find the initial height from which the rock was thrown. The first step on this process is to determine the time the rock was in the air. We know that the range (horizontal distance) d is given by the equation d=v*t*cos(θ), where v is the initial speed, t is the time the rock is in the air, and θ is the launch angle. Rearranging for time gives us t=d/(v*cos(θ)).

The next step is to apply this time to the vertical motion. The vertical motion is affected by gravity, and the displacement h is given by the equation h=vi*t - 0.5*g*t², where vi is the initial vertical speed, which is given by v*sin(θ), and g is the acceleration due to gravity. As the rock is hitting the ground, h will be negative. Substituting all the known values will give us the initial height the rock was thrown from.

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Answer: Option (b) is the correct answer.

Explanation:

As Kristina is over training, therefore, there is pain in her muscles because human body also requires rest in order to work or function properly.

That is why, gym trainers suggest to give one day off in a week for your workout sessions so that body muscles should recover.

Thus, we can conclude that if Kristina is over training, then recovery training principle should Kristina consider before continuing her program.

Answer:

B

Explanation:

The formula for calculating wavelength ʎ is:

ʎ = s / f

where ʎ is wavelength, s is speed of sound, f is frequency

ʎ (large organ pipe) = (344 m/s) / (30 s-1) = 11.47 m

ʎ (piccolo) =  (344 m/s) / (1.5x10^4 s-1) = 0.023 m

So the difference is:

11.47 – 0.023 = 11.45 m

Answer:

11.45 m

The difference in wavelength between the lowest frequency of a large organ pipe and the highest frequency of a piccolo, with the speed of sound at 344 m/s, is approximately 11 m.

The question asks to calculate the wavelength difference between the lowest frequency of a large organ pipe and the highest frequency of a piccolo, given the speed of sound in air at room temperature. The speed of sound in air at 21°C is typically around 344 m/s. The frequency for the organ pipe is 30 s⁻¹ (30 Hz), and for the piccolo, it's 1.5×10⁴ s⁻¹ (15,000 Hz). To find the wavelengths, we use the formula λ = v/f, where λ is the wavelength, v is the speed of sound, and f is the frequency. Thus, for the organ pipe, the wavelength is λ = 344 m/s / 30 s⁻¹ = 11.47 m, and for the piccolo, λ = 344 m/s / 1.5×10⁴ s⁻¹ = 0.0229 m. The difference in wavelength, to two significant figures, is about 11 m.

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Short-range forecasts are typically more accurate than longer-range forecasts because they use near future data and can provide detailed specifics about the weather, which is difficult to maintain over a longer time span.

In weather forecasting, short-range forecasts usually tend to be more accurate than longer-range forecasts. This is because the short-range forecasts use models that are based on current and near-future atmospheric conditions, which predict the weather for 1 to 3 days. On the other hand, longer-range forecasts predict weather for a period of 3 to 7 days or even up to several months, and although they can give a general pattern of the weather to be expected, they can't provide detailed specifics like short-range forecasts do. Therefore, short-range forecasts are typically more reliable than longer-range forecasts due to the complexities and variabilities involved in predicting atmospheric conditions over a long time span.

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Answer:

14545 .45 N

Explanation:

The weight of given car is 3200 lb.

0.22 lb = 1 N            (Given)

[tex]1 = \frac{1}{0.22}N/lb[/tex]

Therefore, the weight of the car in N can be calculated as follows:

[tex]3200 lb =3200 lb\times \frac{1}{0.22}N/lb=14545 .45 N[/tex]

Answer:

0.35 m/s^2 or 0.35 m/s squared

Explanation:

Answer:The distance of Mercury from the Sun in kilometer is [tex]5.8344\times 10^7 km[/tex].

Explanation;

Distance between the Mercury and Sun = 0.39 AU

1 AU = [tex]1.496\times 10^8 km[/tex]

So, 0.39 AU = [tex]0.39\times 1.496\times 10^8 km=5.8344\times 10^7 km[/tex]

The distance of Mercury from the Sun in kilometer is [tex]5.8344\times 10^7 km[/tex].