You are driving your car on a very cold late Fall day. You clear a turn and see a couple of pedestrians standing at the cross walk. They are eager to cross the road and to get into the warmth of their apartment as soon as possible. You have two options: continue driving your car as you were without lowering your speed and drive right by the pedestrians OR slow down, stop right at the crosswalk, and yield to the pedestrians. Although by Virginia law the choice is clear, what about Physics laws? Which scenario (passing by or slowing down and stopping at the crosswalk to yield) will minimize the time the pedestrians are out in the cold freezing before they can cross the road?
Make the following assumptions in your argument. Before you noticed the pedestrians, you are moving with a constant velocity v=22 miles/hour. The distance at which you noticed the pedestrians is D=23 meters. Write down a symbolic expression for the amount of time, tpass , the pedestrians will have to wait till they cross the road if you simply drive by without slowing down or speeding up.
Write down a symbolic expression for the amount of time, tstop, the pedestrians will have to wait till they cross the road if you slow down, come to a complete stop at the crosswalk and yield to the pedestrians.

Answer:

24.5 m/s

Explanation:

KE=1/2mv^2

15000=1/2(50)v^2

30000=(50)v^2

600=v^2

sqrt600=v

v=24.5 m/s!!

Answer:

one sec let me think

Explanation:

(a)The average velocity of the ball over the following time intervals will be  [3,4] ft/sec.

(b)The instantaneous velocity at time t = 3 will be32 ft/sec.

(c)The instantaneous velocity at time t = 6 will be -64 ft/sec.

(d)The ball will hit the ground at 13.4 sec.

The change of displacement with respect to time is defined as the velocity.  velocity is a vector quantity. it is a time-based component.

The given data in the question will be ,

u is the initial velocity by which ball thrown=128 ft/sec.

V₃ is the instantaneous velocity at time t=3 sec.

V₆ is the instantaneous velocity at time t=6 sec.

t is the time when ball hits the ground=?

(a) Given equation for the displacement

s(t) =128t-16t²     (on differenting got the velocity )

v(t) = 128-32t

Time when velocity is zero will be

[tex]\rm{ t=\frac{128}{32}[/tex]

[tex]\rm{ t=4 sec[/tex]

If the velocity got in the equation is 128 and 32 ft /sec. it can be only when the average velocity is [3,4] ft/sec .

Hence the average velocity obtained from the problem will be  [3,4] ft/sec

(b)  

s(t) =128t-16t²     (on differenting got the velocity )

v(t) = 128-32t

At time( t=3 sec)

v(3) = 128-32×3

v(3) =32 m/sec.

Hence the instantaneous velocity at time t = 3 will be32 ft/sec.

(c)

s(t) =128t-16t²     (on differenting got the velocity )

v(t) = 128-32t

At time( t=6 sec)

v(6) = 128-32×6

v(6) = -64 m/sec.

Hence the instantaneous velocity at time t = 6 will be -64 ft/sec.

(d)

According to Newtons third equation of motion we got

v=u+gt

If the body returens from a certain height at max height its velocity must be zero; ( u=0)

[tex]\rm t=\frac{(v-u)}{g} \\\\\ \rm t=\frac{(128-0)}{9.81}\\\\\rm t=13.04 sec.[/tex]

Hence the ball will hit the ground at 13.4 sec.

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Answer:

Thermal Energy

Explanation:

The energies that work together to bake the bread and cook the eggs is the thermal energy. Thermal energy is basically heat energy, which makes the food warmer.

Thermal energy and chemical energy work together to bake the bread and cook the eggs.

The energy present in a system that determines its temperature is referred to as thermal energy. Thermal energy flows as heat. Thermodynamics is a whole field of physics that studies how heat is transmitted across various systems and how work is done in the process.

Chemical energy is described as: the power that is kept in chemical compound bonds (molecules and atoms). It is released during the chemical process, which is referred to as an exothermic reaction, which mostly generates heat as a byproduct.

When the bread is baked or the eggs are cooked, thermal energy is provided from outside and  chemical energy inside the molecules of bread  or eggs come to play. So, these two energies work together to bake the bread and cook the eggs.

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6 floors down from 12 floors underground = 18 floors underground.

6 degrees colder than 12 degrees below zero  =  18 degrees below zero

6 brown cows taken away from -12 brown cows = -18 brown cows

6 cars sold from a dealer that 12 cars were stolen from = 18 cars gone

6xy taken away from -12xy  =  -18xy

Answer:

rotates

Explanation:

I'm so bored

yrfgggghhgghhyuj

Answer:

a. 20 s

b. 0 m/s  

c. right

d.no its inelastic because when the car b was at rest and a was coming in at it, since b had no force what so ever car a swept it away with it moving to the right

Explanation:

im not sure though

By applying conservation of linear momentum, the answers are:

1. Time = 2 s

2. 3 m/s

3. same direction

4. Inelastic collision

There are for types of collision. They are;

Given that a local church is hosting a carnival which includes a bumper car ride. Bumper car A and its driver have a mass of 300 kg; bumper car B and its driver have a mass of 200 kg. Bumper car A has a velocity to the right of 2 m/s and bumper car B is at rest. At t = 0 s, bumper car A and B are separated by 10 m. Bumper car A accelerates at 1 m/s2 to a velocity of 4 m/s and continues at this constant speed until colliding with bumper car B.

1. The time required for bumper car A to travel the 10 m to collide with bumper car B can be calculated by using first equation of linear motion.

V = U + at

Where

V = 4 m/s

U = 2 m/s

a = 1 m/[tex]s^{2}[/tex]

Substitute all the parameters into the formula

4 = 2 + t

t = 4 - 2

t = 2s

2. To calculate the speed of bumper car A following the collision with bumper car B, which now has a velocity to the right of 3 m/s, we will apply conservation of linear momentum

[tex]m_{1}u_{1}[/tex] = [tex]m_{1}v_{1}[/tex] + [tex]m_{2}v_{2}[/tex]

300 x 4 = 300V + 200 x 3

1200 = 300V + 300

300V = 1200 - 300

300V = 900

V = 900/300

V = 3 m/s

3. Since the final velocity of car A is positive, the direction of motion for bumper car A follows the collision with bumper car B to the right.

4. Since the both move at the same velocity, the collision inelastic.

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Answer:

An object is considered to be in motion only when its position changes over time with reference to a point which will be known as orgin

Answer:

(a) The change in momentum is 12.04 kg-m/s

(b) The force exerted by the bat is 1003.33 N

Explanation:

Given that,

The mass of a ball, m = 0.14 kg

Initial speed of the ball, u = 40 m/s

Final speed of the ball, v = -46 m/s

(a) The change in momentum of the ball during the collision with the bat is given by :

[tex]\Delta p=m(v-u)\\\\=0.14(-46-40)\\\\=-12.04\ kg-m/s[/tex]

(b) Time for collision, t = 0.012 s

Now the force can be calculated as follows :

[tex]F=\dfrac{\Delta p}{t}\\\\F=\dfrac{12.04}{0.012}\\\\=1003.33\ N[/tex]

Hence, this is the required solution.

Answer:

a. = 12.04 kg*m/s

b. = 1,003.3N

Explanation:

The answer above is correct.

Answer:

c

Explanation:

Answer:

it’s cosmopolitan

Explanation:

k12

The weight is measured in a unit called Newton. The newton is a standard unit of weight measurements.

The International System of Units (SI) uses Newtons (N) as the unit of weight measurement. Weight is frequently expressed in pounds (lb) or ounces (oz) in some nations that employ the Imperial system. However, Newton is the accepted weight measurement unit in scientific and international contexts.

The International System of Units (SI) uses Newton as the primary unit of weight measurement. Sir Isaac Newton, a great physicist who significantly influenced our understanding of classical mechanics, is honored by having his name attached to it. Newton is the force needed to accelerate a mass of one kilogram by one meter per second squared in the SI system.

Hence, the weight is measured in a unit called Newton. The newton is a standard unit of weight measurements.

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[tex]\mathfrak{\huge{\orange{\underline{\underline{AnSwEr:-}}}}}[/tex]

Actually Welcome to the Concept of the Waves.

Wavelength is the distance between two consecutive crest or trough.

hence, here the distance is 10cm

So the wavelength is 10cm

===> 10 cm

Answer: The main difference between the three is the mode of transmission. The chest pass is straight through the air towards your teammate. While the bounce pass is directed toward the ground and then at your teammate. Finally, the overhead pass is projected high in the air to avoid defenders.

Explanation:

Answer:

The main difference is: the chest pass is straight through the air towards your teammate. While the bounce pass is directed toward the ground and then at your teammate.

The secondary main difference is the amount of power from the ball recived from the person reciving

Answer:

Me encanta el pollo, de todos modos, un día que es hoy, por cierto, fui a la tierra de los pollos y caminé en México, ¿sabías que es mi sueño? ¿Olvidé que mi nombre es jemma y me gusta caminar? párrafo así que nos vemos

Explanation:

Answer:

Fluorine needs to gain only 1 electron to have a full octet, while nitrogen needs to gain 3.

Answer:

B is the Answer

Follow me please

Mark brainliest

Answer:

The answer is A

Explanation:

This is because f = 1/T,

or frequency equals 1 over period, T

Since the highest T would be the answer with the greatest length and mass does not matter the answer would be c IF they were asking for the highest period.

F is found by 1 over T so the greatest F would be the smallest number, Hence answer A

Please Mark me brainiest

Answer:

what situation?

Explanation:

Answer:

160.43 meters

Explanation:

T=(2*pi*r)/v

840=(2*pi*r)/1.2

1008=2*pi*r

504=pi*r

160.43=radius

The distance around the circular track is equal to its circumference. If it takes840 s  to complete the path with a velocity of 1.20 m/s then the radius of the path will be 160 m.

Velocity is a physical quantity measuring the distance traveled by unit time. It is a vector quantity thus, characterized by its magnitude and direction. Velocity is usually expressed in m/s.

Velocity is the ratio of distance to the time taken to complete the travel. Thus, greater distance within short time indicates greater velocity.

Given that the time take to complete the circular path = 840 s

velocity = 1.20 m/s

distance = circumference of the circular path = 2πr.

distance = time × velocity

2πr = 840 s × 1.20 m/s

      = 1008 m.

Therefore, the radius r of the circular path  = 1008 m/ 2 π = 160 m.

Hence, the radius of the circular path 160 m.

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Answer:

a)       [tex]- ( g - \frac{q}{m} \frac{\sigma }{ 2 \epsilon_o} ) \frac{sin \theta}{R }[/tex] =  [tex]\frac{d^2 \theta}{d t^2}[/tex]

b)     f = 2π  [tex]\sqrt{ \frac{R}{ g - \frac{q}{m} \frac{\sigma }{2 \epsilon_o} } }[/tex]  

Explanation:

a) To have the equations of motion, let's use Newton's second law.

Let's set a reference system where the x-axis is parallel to the path and the y-axis is in the direction of tension of the rope.

For this reference system the tension is in the direction of the y axis, we must decompose the weight and the electrical force.

Let's use trigonometry for the weight that is in the vertical direction down

             sin θ = Wₓ / W

             cos θ = W_y / w

             Wₓ = W sin θ

             W_y = W cos θ

we repeat for the electric force that is vertical upwards

              F_{ex} = F_e sin θ

              F_{ey} = F_e cos θ

the electric force is

               F_e = q E

where the field created by an infinite plate is

               E = [tex]\frac{ \sigma}{2 \epsilon_o}[/tex]  

let's write Newton's second law

Y  axis  

           T - W_y = 0

            T = W cos θ

X axis

            F_{ex} - Wₓ = m a                   (1)

we use that the acceleration is related to the position

            a = dv / dt

            v = dx / dt

where x is the displacement in the arc of the curve

substituting

            a = d² x /dt²

we substitute in 1

           q E sin θ - mg sin θ = m [tex]\frac{d^2 x}{dt^2}[/tex]

we have angular (tea) and linear (x) variables, if we remember that angles must be measured in radians

           θ = x / R

           x = R θ

we substitute

           sin θ (q E - mg) = m \frac{d^2 R \ theta}{dt^2}  

          [tex]- ( g - \frac{q}{m} \frac{\sigma }{ 2 \epsilon_o} ) \frac{sin \theta}{R }[/tex] =  [tex]\frac{d^2 \theta}{d t^2}[/tex]

this is the equation of motion of the system

b) for small oscillations

         sin θ = θ

therefore the solution is simple harmonic

      θ = θ₀ cos (wt + Ф)

if derived twice, we substitute

- ( g - \frac{q}{m} \frac{\sigma }{ 2 \epsilon_o}  ) \frac{\theta}{R } θ₀ cos (wt + Ф) = -w² θ₀ cos (wt + Ф)

       w² =  [tex]\frac{g}{R}[/tex] - [tex]\frac{q}{m} \frac{ \sigma }{2 \epsilon_o} \frac{1}{R}[/tex]  

angular velocity is related to frequency

       w = 2π f

        f = 2π / w

        f = 2π/w

        f = 2π  [tex]\sqrt{ \frac{R}{ g - \frac{q}{m} \frac{\sigma }{2 \epsilon_o} } }[/tex]  

Answer:

83.2 m/s to the West

Explanation:

From the question given above, the following data were obtained:

Mass of plane = 180 Kg

Mass of pilot = 70 Kg

Momentum = 20800 Kg∙m/s West

Velocity =?

Next, we shall determine the total mass. This can be obtained as follow:

Mass of plane = 180 Kg

Mass of pilot = 70 Kg

Total mass =?

Total mass = Mass of plane + Mass of pilot

Total mass = 180 + 70

Total mass = 250 Kg

Finally, we shall determine the velocity. This can be obtained as follow:

Total mass = 250 Kg

Momentum = 20800 Kg∙m/s West

Velocity =?

Momentum = mass × Velocity

20800 = 250 × Velocity

Divide both side by 250

Velocity = 20800 / 250

Velocity = 83.2 m/s West

Thus, the velocity of both plane and pilot is 83.2 m/s to the West

Answer:

)Give the definition of poverty line as defined by the World Bank.

Answer:

2.2 ma

Explanation:

Given :

Length of the rope = L

Mass of the rope = m

Mass of the object pulled by the rope = M

M = 1.5 m

So, L [tex]$\rightarrow$[/tex] m

For unit length [tex]$\rightarrow \frac{m}{L}$[/tex]

∴ 0.3 L = [tex]$0.3 \ L \left(\frac{m}{L}\right)$[/tex]

            = 0.3 m

And for remaining 0.7 L =  [tex]$0.7 \ L \left(\frac{m}{L}\right)$[/tex]

            = 0.7 m

By Newtons law of motion,

F - T = ( 0.3 m) a .........(1)

T = ( M + 0.7 m) a

T = ( 1.5 m + 0.7 m) a

T = ( 2.2 m ) a  ..............(2)

So from equation (1) and (2), we have

Tension on the rope

T = 2.2 ma

Answer:

a = 1,538 m / s²

Explanation:

Let's use Newton's second law, let's set a reference system where the x-axis is parallel to the sloping floor of the truck and the positive direction is in the direction of movement of the trough, for this case the weight is the only force to decompose

          sin θ = Wₓx / W

          cos θ = W_y / W

          Wₓ = W sin θ

          W_y = W cos θ

Y axis

          N -W_y = 0

          N = mg cos θ

X axis

          Wₓ - fr = m a

the friction force has the expression

          fr = μ N

There are values ​​of the friction coefficient (μ_s) one for when the movement has not started and it takes a smaller value for when the bodies are moving.

In this case we first find the angle for which the movement begins, in this part we use the static coefficient and the acceleration is zero

             Wₓ - μ_s N = 0

             m g sin θ = μ_s mg cos θ

             tan θ = μ_s

             θ = tan⁻¹ μ_s

we calculate

              θ = tan⁻¹ 0.8

              θ = 38.7º

For this angle, how the trough begins to move, the coefficient is reduced to the dynamics coefficient (μ_k)  and the acceleration is different from zero.

we substitute

          mg sin θ - μ_k mg cos θ = m a

          a = g (sin θ - μ_k cos θ)

let's calculate

          a = 9.8 (sin 38.7 - 0.6 cos 38.7)

          a = 1,538 m / s²

Answer:

Examples of compound machines include bicycles, cars, scissors, and fishing rods with reels. Compound machines generally have lower efficiency but greater mechanical advantage than simple machines

Brilianst

Answer:

screws, inclined planes , etc

Explanation:

no explanation needed