I don't know what I'm doing wrong I just can't seem to get the answers right. Help please.

Answer:

a) She get detention for being late again

Explanation:

First, we need to identify how much time does she take on each hallway.

With the distance and the speed, we can calculate the time as:

t = distance/speed

So, for each hallway, we get:

First hallway:

distance = 35 m

speed = 3.5 m/s

time = 35/3.5 = 10s

Second Hallway

distance = 48 m

speed = 1.2 m/s

time = 40s

Third Hallway

distance = 60 m

speed = 5 m/s

time = 60/5 = 12 s

Therefore, the total time that she takes was

10s + 40s + 12s = 62s

Since she takes more than 60 seconds, she will be late again.

Finally, we know that she takes 10s to run a distance of 35m, then another 40s to run a distance of 48 m, and another 12s to run a distance of 60 m. Therefore, the distance vs. time graph for this situation is

ANSWER

C. The total (PE + KE) before an event is equal to the total (PE + KE) after the event.

EXPLANATION

We want to identify the correct option.

The law of conservation of energy is a law that applies only to closed systems and it states that:

In other words, energy cannot be created nor destroyed.

This implies that the total energy (sum of potential and kinetic energy) before an event occurs must be equal to the total energy after the event has occurred.

Therefore, the correct option is option C.

The correct answer to the statement " Do two bodies have to be in physical contact to exert a force upon one another " is:

No, the gravitational force is a field force and does not require physical contact to exert

a force.

The correct option is a.

It has been practically proven that two bodies can exert a force upon each other even if there is no physical contact between them. This can as a result of gravity.

That being said, a magnetic attraction can also exert a force between two different bodies upon one another.

So therefore, it can be deduced from above that two different bodies do not have to be in physical contact before they exert a force upon one another.

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When exercising in the heat, you should wear tight - fitting clothes to absorb your sweat, therefore the correct answer is option A.

Exercise is a physical activity that involves bodily movement that improves a person's health, fitness, and well-being while lowering their chance of contracting illnesses.

Dressing in layers is useful in extreme cold conditions and extremely cold weather.

Dark-colored clothing absorbs more heat as compared to light - colored clothing.

When exercising in the heat, you should wear tight-fitting clothes to absorb your sweat, therefore the correct answer is option A.

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The exact point of an object measured from all its edge center of mas.

What is center of mass?

the center of mass of a distribute of mass in space is the unique point where the weighted relatively position of the devided mass sums to 0. This is a point to which a force of  may be applied to cause of a  linear acceleration it without an angular acceleration.

Most of the time (not everytime)the centre of mass of an object lies within the object itself.

Eg-the center of mass of a ball in middle of a ball and the centre of mass of a copy is middle of a copy.

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The output of this device is equal to 550 000-315 000 = 235 000, or 42.7%, of its energy efficiency.

Efficiency is the percentage of input work that is actually completed by the machine (output work). The fact that some of the input work is used to reduce friction is the main cause of the output work always being less than the input labor. Efficiency is never 100% and is therefore always less than 100%..

Due to internal friction, simple machines are always less efficient than 1.0. conserving energy When friction is ignored, the work performed on a simple machine is equivalent to the work performed by the machine to complete a task.

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D. increased speed; acceleration is the correct description of that graph.

Shown far an item has come in a certain amount of time is displayed on a distance-time graph. The graph that shows the results of the distance vs time analysis is a straightforward line graph. The Y-axis represents the distance.

A sloping line on a distance-time graph shows that an item is moving. In a distance-time graph, the object's speed is equal to the slope or gradient of the line. The line becomes steeper as the thing goes more quickly (and the greater the gradient).

The horizontal line on a graph of a distance vs time indicates that the item is at rest because the distance does not change over time.

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Habituation is a term does this situation exemplify.

In this case, the professor is talking about a situation where a person has become used to a particular stimulus. as a result, the rate at which the stimulus would be registering to the person would be much lesser as compared to someone who is fairly new in being exposed to the stimulus.

This process is called habituation. Sensitization is the situation where a person becomes extremely sensitive to even lower intensity of the stimulus.

Habituation is a form of non-associative studying in which an innate reaction to a stimulus decreases after repeated or prolonged presentations of that stimulus. Responses that habituate encompass those who involve the intact organism or those that contain simplest additives of the organism.

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To send information through verbal speech, transmitter cords send information encoded in radio waves through the air.

The basic principle is simple. At one end a transmitter encodes or modulates the message by varying the amplitude or frequency of the waves. This is a bit like Morse code. Meanwhile, a receiver tuned to the same wavelength receives the signal and decodes it into the desired format sound image data, etc.

Communications and satellite transmissions. Radio waves travel easily through the air. Radio waves are used for the wireless transmission of sound messages and information for communications, and for maritime and air navigation. Information is applied to an electromagnetic carrier wave as amplitude modulation AM frequency modulation FM or digital form pulse modulation.

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Given:

Velocity = 40 m/s

Angle = 37°

Let's find the distance from the cnnon where you should place a matress to catch the human if the muzzle is 0.75 meters from the ground.

Let's first draw the projectile motion diagram:

To find the distance, first apply the formula to solve for the time taken for the human to reach the matress.

Where:

Height from the ground to the muzzle = yo = 0.75

y = 0

Velocity = vo = 40 m/s

initial vertical velocity = voy = vo sinθ = 40 sin37

We have:

g is the acceleration due to gravity = 9.8 m/s²

Now, let's solve for the time t:

To sove for the horizontal distance, x, apply the formula:

Hence, we have:

Therefore, the matress should be placed at 157.8 meters from the cannon in order to catch the human.

ANSWER:

157.8 meters

Given

Three electrically charged spheres A,B and C. Sphere A is brought near Sphere B and both are attracted to each other electrically. Sphere B is brought near Sphere C and both repel each other electrically.

To find

What happens when Sphere A is brought near Sphere C?

Explanation

Sphere A and sphere B are attracted to each other.

Thus, both A and B are of opposite charge.

Let A be a positive charge and B be a negative charge.

When sphere B is brought near sphere C both repel.

Thus, sphere C is also of negative charge.

So A and C are then of opposite charges and would both attract each other.

Conclusion

When sphere A is brought near sphere then C)electrical attraction occurs.

If the earth has a radius R of about  6.37 × 10⁶ m, then the power received by the earth would be 2.722 × 10¹⁰ watts.

The rate of doing work is known as power. The Si unit of power is the watt.

Power =work/time

As given in the problem Earth has a radius R of about 6.37 × 10⁶ m.

Area of the earth assuming it is a circle = 3.14 × 6.37 × 10⁶

                                                                 = 2 × 10⁷ meter²

The power received by the earth = 2 × 10⁷ × 1361

                                                       = 2.722 × 10¹⁰ watts

Thus, the power received by the earth would be 2.722 × 10¹⁰ watts.

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We are asked to determine the force exerted on the object. To do that we will use Newton's second law:

Where:

Now, we substitute the values:

Solving the operations:

Therefore, the force is 9N.

A body is considered to be discharged when it loses charge to the ground or another body.

The human body is an excellent conductor. Therefore, that will fall to the earth as the Charge passes through our bodies. Discharge of the body is the process by which the excess energy leaves the body and flows through it before falling to the ground. The term "earthing" refers to this idea.

Allowing the electricity to discharge from your body into the ground is the quickest approach to eliminating static electricity from the body. Touch any conductive object that is not isolated from the ground to enable this, such as a metal light pole or the screw on a light switch panel.

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The angular velocity is obtained from the calculation as 13.7 rad/s.

Let us recall that the term circular motion is applied to the kind of motion that is carried out by an object that is moving along a circular path. Given the fact that we have an object that is spinning around in a circular path, we can say that a circular motion is actually taking place in the system that involves the athlete, the ball and the rope.

We are told that the athlete is 181cm tall, with an arm length of 90 cm and is using a standard ball and chain for the event which is 121cm long. As the athlete begins to spin , their body becomes the center of the motion, with both arms holding on to the ball and chain handle then the initial linear velocity of the ball and chain is 29m/s upon its release.

We can now see that the radius of the path is 90 cm + 121 cm = 211cm or 2.11 m

Using;

V = rω

ω = V/r

ω =  29m/s/2.11 m

ω = 13.7 rad/s

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ANSWER:

-3.73 m/s^2

STEP-BY-STEP EXPLANATION:

Acceleration is the rate of change of velocity and we can calculate it as follows:

Replacing:

The baseball's player's deceleration is 3.73 m/s^2

The magnitude of your horizontal acceleration as you begin to slow is 7.35m/s².

Applying work-energy theorem,

Total work done on the body by all the forces = change in kinetic energy.

So, here,

Work done by friction = ∆KE

-uMgd = 1/2M(v²-u²)

u is the coefficient of friction,

M is the mass of the car,

g is the acceleration due to gravity,

v is the final velocity of car,

u is the final velocity of car,

d is the horizontal distance moved by car.

(-0.75)(1800)(9.8)d = -1/2(1800)(21)²

d= 30 meters.

Applying Equation of motion,

V²-U²=2ad

Where a is the horizontal acceleration,

-(21×21) = 2(30)a

a = 7.35m/s².

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Answer: 85.4 km/h

Explanation:

We would apply the law of conservation of kinetic energy. The formula is expressed as

KE1 + PE1 = KE2 + PE2

where

KE1 and KE2 are the initial and final kinetic energies

PE1 and PE2 are the initial and final potential energies

The formula for calculating kinetic energy is

KE = 1/2mv^2

where

m is the mass of the object

v is the velocity

The formula for calculating potential energy is

PE = mgh

where

g is the acceleration due to gravity = 9.8m/s^2

h is the height of the object

From the information given,

m = 55

h = 8.3

Potential energy at the top = 55 x 9.8 x 8.3 = 4473.7

At the top, v = 72km/h

Recall, 1 km = 1000m

1 hour = 3600s

72km/h = 72 x 1000/3600 = 20m/s

kinetic energy at the top = 1/2 x 55 x 20^2 = 11000

KE1 + PE1 = 4473.7 + 11000 = 15473.7

At the point of landing,

PE2 =0

KE = 1/2 x 55 x v^2 = 27.5v^2

Thus,

27.5v^2 = 15473.7

v^2 = 15473.7/27.5

v = √(15473.7/27.5)

v = 23.72 m/s

his landing speed is 23.72 m/s

Converting to km/h, we would multiply 23.72 by 18/5

Landing speed = 85.4 km/h

In order to calculate the speed of the spacecraft, use the following formula;

where,

M: mass of the moon = 7.3*10^22 kg

G: Cavendish constant = 6.67*10^-11 Nm^2/kg^2

r: distance in between the spacecraft and the center of the Moon =

172 km + 1840 km = 2012 km

Replace the previous values of the parameters into the formula for v and simplify:

Hence, the speed of the spacecraft is approximately 4.91*10^4 m/s

The magnitude of the force F exerted by the leg on the small pulley is, F = 38.53 N

We can calvulate the magnitude of the force by a mathematical calculation, which is as follows. As the small pulley and mass are not moving, they are stationary.

t2=t1 = mg = (2.27)(9.8)

= 22.246 N

Now resolve the force in the opposite direction.

F = 2Tcos30°

F = (2)(22.246)(cos30°)

F = 38.53 N

Therefore, the magnitude of the force is 38.53 N.

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ANSWER

EXPLANATION

First, let us make a sketch of the problem:

where r = angle of refraction

d = depth of the pool

First, we have to find the angle of refraction, r, by applying Snell's law:

where n1 = incident refractive index = 1

n2 = refracted index = 1.33

i = angle of incidence = 70°

Therefore, solving for r, we have that:

Now, we can solve for the depth of the pool by applying trigonometric ratios for right triangles for tangent:

That is the depth of the pool.

According to the zeroth law of thermodynamics, no heat is transferred between the two objects if both the objects are at the same temperature.

Thus, no heat transfer between the water, pot, and air occurs according to the zeroth law of thermodynamics.

Hence, the zeroth law of thermodynamics is the correct answer.

If the angular velocity id doubled, then the linear speed of the boy will be doubled.

As we know,

If a body is rotating in a circular path, it will have an angular as well as linear velocity.

The angular velocity is responsible for rotation and the linear velocity is responsible for changing the direction in a circular manner.

The angular velocity W is related to the linear velocity V as,

W = V/R

Let us say this is equation 1,

Where R is the radius of the merry go round,

Now if the angular velocity is doubled,

W' = V'/R

Let us say this is equation 2.

On dividing equation 1 and 2,

W/W' = V/V'

As we know, W' = 2W.

1/2 = V/V'

V' = 2V.

The linear velocity will increase by a factor of 2.

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The impulse is mathematically given as

v_f=3.61m/s

This is further explained below.

Generally, In classical mechanics, the integral of a force F over the time period t during which it operates is referred to as the impulse of the system.

It should come as no surprise that impulse is likewise a vector quantity given that force is one.

When an impulse is applied to an item, a corresponding vector change in the object's linear momentum occurs, also in the direction that the impulse causes.

In conclusion, Impulse = Area Under Curve

             =2*4+1*4

  [tex]m\left(v_f-v_i\right)=12 \\\\v_f=\frac{12}{2.35}=5.11 \mathrm{~m} / \mathrm{s}\\\\m\left(v_f-(-1.5)\right)=12 \\v_f=5.11-1.5 \\\\ =3.61 \mathrm{~m} / \mathrm{s} \\v_f=3.61 \mathrm{~m} / \mathrm{s}\end{gathered}$$[/tex]

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CQ

A force of magnitude Fx acting in the x-direction on a 2.35-kg particle varies in time as shown in the figure below.

(a) Find the impulse of the force.

____________kg

Answer:

The development of the electron microscopes therefore helped scientists to learn about the sub-cellular structures involved in aerobic respiration called mitochondria . The scientists developed their explanations about how the structure of the mitochondria allowed it to efficiently carry out aerobic respiration.

Given:

The charge on the capacitor is Q = 0.617 nC

The distance between plates is d =1.784 mm

The area is

To find the electric field strength.

Explanation:

The electric field strength can be calculated by the formula

The constant is

On substituting the values, the electric field strength will be

The resultant of the two given vectors with magnitudes 16.3 m and 7.7 m at an angle of 137.8 degree is equal to 23.87 meters.

What is the parallelograms law of vector addition?

If two vectors are acting simultaneously at a point, then it can be represented both in magnitude and direction by the adjacent sides drawn from a point.

What is the trigonometric ratio?

Trigonometric Ratios are defined as the values of all the trigonometric functions based on the value of the ratio of sides in a right-angled triangle. The ratios of sides of a right-angled triangle with respect to any of its acute angles are known as the trigonometric ratios of that particular angle.

Given:

Vector 1 of magnitude 7.7 m at an angle of 27.8 degree to x-axis.

vector 2 of magnitude 16.3 m at an angle of 20 degree to minus y axis.

Using the law of parallelogram vector addition

i.e.

resultant vector = √((v₁) ² + (v₂) ² + 2 × v₁ × v₂ × cos (angle between two vectors))

substituting given value in parallelogram vector addition we get,

resultant vector = √ (570)

resultant vector = 23.87 meters

therefore, the resultant of the two given vectors with magnitudes 16.3 m and 7.7 m at an angle of 137.8 degree is equal to 23.87 meters.

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Answer:

11.79

Explanation:

First, for us to start, let us draw the problem:

When we analyse this problem, we can see that the only velocity that changes overtime is the vertical velocity (due to gravity), so the horizontal speed is the same throughout the whole movement. This gives us the following:

Then, the horizontal speed at the peak of the trajectory (and also during the whole movement) is v=36.546m/s

22920 years old is an artifact if four half-lives have occurred and the half-live of carbon-14 is 5730 years.

Due to radioactive decay to nitrogen-14, carbon-14 has a very short half-life of 5,730 years, which means that over this time, the proportion of carbon-14 in a sample will have decreased by 50%.

A half-life is the amount of time it takes for something to go from 100% to 50%. The phrase is most frequently used in reference to radioactive decay, which happens when energetic atomic particles that are unstable lose momentum.

The half-life of carbon-14 is 5730 years. Accordingly, a sample of 100 carbon-14 atoms has a half-life of 5730 years, or 50 carbon-14 and 50 carbon-12 (i.e., 100 carbon-14, one half-life = 50 carbon-14, 50 carbon-12).

4 half lives

=5730×4

=22,920 years old.

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