Physics High School

## Answers

**Answer 1**

**Answer:**

El conductor no puede evitar el choque.

**Explanation:**

Primero, convierta la velocidad del conductor a m / s:

1 km/h = 0.277778 m/s

126 km/h = 126 * 0.277778 = 35 m/s

La velocidad del automóvil es de 35 m / s.

El conductor presiona los frenos con una aceleración de -3.5 m / s² para evitar un choque a 150 m por delante.

Veamos qué distancia se moverá el automóvil después de que comience a desacelerar.

Utilizaremos una de las ecuaciones de movimiento lineal de Newton:

[tex]v^2 = u^2 + 2as[/tex]

donde v = velocidad final = 0 m / s (el automóvil debe detenerse)

u = velocidad inicial = 35 m / s

a = aceleración = -3.5 m / s².

s = distancia recorrida

Por lo tanto:

[tex]0 = 35^2 + (2 * -3.5 * s)\\\\=> 1225 = 7.0s\\\\s = 1225 / 7 = 175 m[/tex]

Esto significa que el automóvil se detendrá a 175 m.

Por lo tanto, a esa velocidad y aceleración, **el conductor chocará contra el árbol caído porque el automóvil no podrá detenerse antes de alcanzar la posición del árbol.**

## Related Questions

A ball has a mass of 0.25 kg and is moving to the right at 1.0 m/s. It hits a ball of mass 0.15 kg that is initially at rest. After the collision, the 0.15 kg ball moves off to the right with a velocity of 0.75 m/s. What is the final velocity of the 0.25 kg ball? 0.42 m/s to the right 0.42 m/s to the left 0.55 m/s to the right 0.55 m/s to the left

### Answers

**Answer:**

C-0.55 m/s to the right

**Explanation:**

edg

**Answer:**

0.55 to the right

**Explanation:**

Oil at 150 C flows slowly through a long, thin-walled pipe of 30-mm inner diameter. The pipe is suspended in a room for which the air temperature is 20 C and the convection coefficient at the outer tube surface is 11 W/m2 K. Estimate the heat loss per unit length of tube.

### Answers

**Answer:**

**1.01 W/m**

**Explanation:**

diameter of the pipe d = 30 mm = 0.03 m

radius of the pipe r = d/2 = 0.015 m

external air temperature Ta = 20 °C

temperature of pipe wall Tw = 150 °C

convection coefficient at outer tube surface h = 11 W/m^2-K

From the above,* we assumed that the pipe wall and the oil are in thermal equilibrium*.

area of the pipe per unit length A = [tex]\pi r ^{2}[/tex] = [tex]7.069*10^{-4}[/tex] m^2/m

convectional heat loss Q = Ah(Tw - Ta)

Q = 7.069 x 10^-4 x 11 x (150 - 20)

Q = 7.069 x 10^-4 x 11 x 130 = **1.01 W/m**

The** heat loss **per **unit length** of **tube** should be considered as the **1.01 W/m.**

Calculation of the heat loss:

Since

**diameter** of the pipe d = 30 mm = 0.03 m

**radius** of the pipe r = d/2 = 0.015 m

**external** air temperature Ta = 20 °C

**temperature** of pipe wall Tw = 150 °C

**convection coefficient** at **outer tube surface** h = 11 W/m^2-K

Now

**area** of the **pipe per unit length **A should be

= πr^2

= 7.069*10^-4 m^2/m

Now

**convectional heat loss** Q = Ah(Tw - Ta)

Q = 7.069 x 10^-4 x 11 x (150 - 20)

Q = 7.069 x 10^-4 x 11 x 130

= 1.01 W/m

hence, The** heat loss **per **unit length** of **tube** should be considered as the **1.01 W/m.**

Learn more about **heat** here: https://brainly.com/question/15170783

Consider a satellite in a circular orbit around the earth. Why is it important to give a satellite a horizontal speed when placing it in orbit? What will happen if the horizontal speed is too small? What will happen if the speed is too large?

### Answers

**Answer:**

In this case, the horizontal velocity of the rocket starts from the acceleration, so if its velocity drops to zero,

**Explanation:**

When a satellite is in orbit the most important force is the docking of gravity with the Earth

F = m a

where the acceleration is centripetal and F is the force of universal attraction

centripetal acceleration is

a = v² / r

F = m v² / r

In this case, the horizontal velocity of the rocket starts from the acceleration, so if its velocity drops to zero, the force also drops to serious and the satellite steels to Earth.

The speed of the satellite is provides the speed, by local for smaller speeds in satellite, it descends in its orbits and when the speed is amate you have the energy to stop an orb to go to a higher orbit.

What is the last step in creating an argumentative essay?

outlining

prewriting

researching

revising

### Answers

**Answer:**

The answer is **Revising**

**Answer:**

D

**Explanation:**

Revising

Choose the friction which opposes the relative motion between surfaces in motion a.Static friction b.Kinetic friction c.Sliding friction d.Both kinetic and sliding friction

### Answers

**Answer:**

**d. Both kinetic and sliding friction**

**Explanation:**

Kinetic friction, commonly known as sliding friction, happens when a body with its surfaces in contact is in relative motion with another. It's the frictional force slowing it down, and finally stopping a moving body. One can describe sliding friction as the resistance any two objects create while sliding against each other. It is often documented as the force required to hold a surface moving along another surface. It is determined by two variables- one is material of the object and another is its weight.

a Porsche 911 accelerates from rest to 27 metre per second due north in 5.8 seconds the mass of the car is 1400 kg what is the magnitude and direction of the average net force

### Answers

**Answer:**

The average force has a magnitude 6524 N due north.

**Explanation:**

The average net force F = ma where m = mass of car = 1400 kg and a = acceleration.

a = (v - u)/t where u = initial velocity of car = 0 m/s (since it starts from rest)

v = final velocity of car = 27 m/s due north and t = time of motion = 5.8 s

a = (27 m/s - 0 m/s)/5.8 s = 27 m/s ÷ 5.8 s = 4.66 m/s

Since the direction of the velocity change is the direction of the acceleration, the acceleration is 4.66 m/s due north.

The average force, F = ma = 1400 kg × 4.66 m/s = 6524 N

Since the acceleration is due north, the average force takes the direction of the acceleration.

So the direction of the average force is due north

The average force has a magnitude 6524 N due north.

21. When air is blown into a balloon, it expands equally in all directions. The best explanation for this is (circle the correct answer): A - The gas molecules in the balloon are expanding B - Internal air pressure acts at right angles to the balloon surface. C - As more air is blown in, the temperature increases causing the balloon to expand.

### Answers

**Answer:**

C

**Explanation:**

I would have said B but air pressure acts at ALL angles(directions). C makes sense because the increase in the temperature would cause the molecules to bounce off the walls of the balloon and each other which exerts pressure.

**Answer:**

C c hagwguawnjaahwbhanwbhsqn2nusbwvwf

A transformer is used to light a lamp rated 40w, 240v from a 400v A.C supply. Calculate:

A. The ratio of the number of turns of the primary to the secondary coil.

B. Current drawn from the main circuit if the efficiency of the transformer is 90%.

### Answers

Answer:1.81

(a) Explanation:the turn ratio= input voltage÷output voltage.

400÷220=1.81.

Don't know how to solve b part...

1. Find the energy required to melt 255g of ice at 0°C into water at 0°C

### Answers

**Answer:**

E = 85170 J (/ 85.2 kJ)

**Explanation:**

Take the latent heat of fusion of water be 334J / g.

From the equation E = ml,

E = energy required (unknown),

mass m = 255g,

latent heat of fusion l = 334J / g,

E = 255 x 334

E = 85170 J (/ 85.2 kJ)

What can happen if a body moves through speed of light

### Answers

As waves travel into the denser medium, they slow down and wavelength decreases.

Explanation:

The denser the medium the slower the waves (speed of light) travels.

◦•●◉✿When the body approaches the speed of light, the body's length appears to contract in the direction of travel, and its mass appears to increase from the point of view of a stationary observer. Only photons move to light velocity. They don´t have length.✿◉●•◦

Answer part (d) please

### Answers

**Answer:**

MARK me brainliest please and follow my page

**Explanation:**

All you have to do to get the average speed is to calculate the total distance covered and divide it by the total time taken

= 16/18 = 0.88m/s

**Average speed = (distance covered) / (time to cover the distance)**

For the full 18 seconds described by the graph . . .

Average speed = (16 meters) / (18 seconds)

Average speed = (16 / 18) m/s

**Average speed = 0.89 m/s**

Even after the body stops moving in a collision, the internal organs are still moving.

### Answers

**Answer:**

True

**Explanation:**

The bodies internal organs move around, even after a collision that may impact your skeletal system.

When a **collision** occurs and the body comes to a sudden stop, the internal organs can continue to move due to their **inertia. **Yes, that statement is generally true.

**Inertia **is the property of an object that resists changes in its state of motion. The** internal organs** of the body, such as the heart, lungs, liver, and others, are not directly attached to the skeletal structure and are instead supported by connective tissues and surrounded by fluids.

During a collision, the body experiences a rapid **deceleration** or change in velocity. While the **external motion **of the body may come to a stop, the internal organs, due to their inertia, continue to move forward momentarily until they are acted upon by internal forces. This phenomenon is known as "**organ motion**" or "organ inertia."

In situations where high-impact** collisions** occur, such as in car accidents or contact sports, the **continued motion** of internal organs can result in serious injuries, even when external signs of trauma may be minimal.

To know more about the moment of **inertia:**

https://brainly.com/question/30051108

#SPJ6

Describe the method you would use to measure the cicrumfrence of a cylinder using a thread and a meter

rule(4mk)

0)

### Answers

**Answer:**

I take the thread and wrap it round the cylinder until it goes round the circumference of the cylinder.

**Explanation:**

I take the thread and wrap it round the cylinder until it goes round the circumference of the cylinder.

I then cut the thread at this length and extend it out on a table or floor.

I then place the length of the thread along the meter rule and mark of the position of its tip and bottom along the meter rule.

The difference between the bottom and top points is the circumference of the cylinder.

If the thread is longer than the meter rule, i mark off where the the length of the meter rule stops along the thread and then place the meter rule at that point and then mark off where the length of the thread stops.

The circumference of the cylinder is then 1 meter plus the extra measurement along the meter rule.

when a 0.622kg basketbll hits the floor its velocit changes from 4.23m/s down to 3.85m/s up. if the averge force was 72.9N how much time was it in contact with the floor?

### Answers

**Answer:**

Time, t = 3.2 ms

**Explanation:**

It is given that,

Mass of basketball, m = 0.622 kg

Initial velocity, u = 4.23 m/s

Final velocity, v = 3.85 m/s

Average force acting on the ball, F = 72.9 N

We need to find the time of contact of the ball with the floor. Let t is the time of contact. So,

[tex]F=ma\\\\F=\dfrac{m(v-u)}{t}\\\\t=\dfrac{m(v-u)}{F}\\\\t=\dfrac{0.622\times (3.85-4.23)}{72.9}\\\\t=0.0032\ s\\\\\text{or}\\\\t=3.2\ ms[/tex]

So, the ball is in contact with the floor for 3.2 ms.

A student throws a 120 g snowball at 7.5 m/s at the side of the schoolhouse, where it hits and sticks. What is the magnitude of the average force on the wall if the duration of the collision is 0.15 s

### Answers

**Answer:**

The magnitude of the average force on the wall during the collision is **6 N.**

**Explanation:**

Given;

mass of snowball, m = 120 g = 0.12 kg

velocity of the snowball, v = 7.5 m/s

duration of the collision between the snowball and the wall, t = 0.15 s

Magnitude of the average force can be calculated by applying Newton's second law of motion;

F = ma

where;

a is acceleration = v / t

a = 7.5 / 0.15

a = 50 m/s²

F = ma

F = 0.12 x 50

**F = 6 N**

Therefore, the magnitude of the average force on the wall during the collision is **6 N.**

A pendulum at position A is released and swings through position B to position Con the other side.

B

1. Describe the total mechanical energy at each of the following positions. (3)

A.

B.

C

### Answers

**Explanation:**

Given the conditions A,B and C when the pendulum is released, at point A the initial velocity of the pendulum is zero(0), the potential energy stored is maximum(P.E= max),

the conditions can be summarized bellow

**point A**

initial velocity= 0

final velocity=0

P.E= Max

K.E= 0

**point B**

initial velocity= maximum

final velocity=maximum

P.E=K.E

**point C**

initial velocity= min

final velocity=min

P.E= 0

K.E= max

coma Narrows Bridge across the Puget Sound collapsed. The bridge was a suspension bridge. The wind blowing through the narrows matched the natural frequency of the bridge. This resulted in a large movement of roadway, which eventually caused the bridge to fail. What characteristic of waves caused the bridge to collapse

### Answers

**Answer:**

amplitude

**Explanation:**

Amplitude is the characteristic of waves which caused the bridge to collapse. Amplitude of a wave is the maximum amount of displacement of a particle occurs in the medium from its rest position. When the frequency of a wave reaches the natural frequency of the bridge, the oscillation of the bridge produce an amplitude where it causing the destruction of the bridge which is called Resonance. So we can say that amplitude is the characteristic of waves which is responsible for the collapse of the bridge.

**Answer: C.interference, because constructive interference occurred when the wind frequency matched the natural frequency of the bridge**

**Explanation:**

Danny lowers the sails on his boat. He paddles upstream at 19 km/hr. The current is still running downstream at 15 km/hr. What is the actual velocity of the boat?

### Answers

**Answer:**

**4 km/hr**

**Explanation:**

The computation of the actual velocity is shown below:

Because the path of its paddles is opposed to the current direction, the real velocity can be determined by deducting the current velocity to its velocity while paddling

So, the actual velocity is

**= Upstream - downstream**

= 19 km/hr - 15 km/hr

= **4 km/hr**

As we can see it is in positive, so it is an upstream direction

**Answer:**

since the direction of his paddles is opposite of the the direction of the current, so the actual velocity can be calculated by subtracting the velocity of current to to his velocity when paddling

v = 19 - 15

v = 4 since the answer is positive, then the direction is upstream

**Explanation:**

Two teams are playing tug-of-war. Team A, on the left, is pulling on the rope with an effort of 5000 N. If the rope is moving at a constant velocity, how hard and in which direction is team B pulling?

A. 2500 N to the left

B. 5000 N to the right

C. 2500 N to the right

D. 5000 N to the left

### Answers

**Explanation:**

If **T****e****a****m**** ****A**** **is on the left, **B**** **is on the right

if the force is constant, it means that the effort applied is equal.

So **T****e****a****m**** ****B**** **is pulling **5****0****0****0****N** to the **r****i****g****h****t****.**

What kind of substance can you pour from one container into another without a change in volume

### Answers

Liquid is the answer

Please mark brainliest please

**Answer:**

Liquids

**Explanation:**

Liquids take up the shape of the container it is poured into but will never change its volume.

Answer the following questions regarding the equation:

N₂ + 3H₂ → 2NH₃

1) indicates what type of reaction is

2) what represents the coefficients 3 and 2 in the previous reaction is done for

3) What would be missing in the previous equation to make it more accurate is

### Answers

**Explanation:**

1) This is a synthesis reaction (two or more reactants combine to form a single product).

2) The coefficients are added to balance the reaction.

3) Adding the states of matter (solid, liquid, gas) will make the reaction more precise.

how does enormous energy get released from the sun

### Answers

**Answer:**

By nuclear fission

**Explanation:**

The sun generates enormous energy through the process of nuclear fusion.

*The core or the innermost part of the sun is characterized by high temperature and pressure. These two factors cause the separation of nuclei from electrons and the fusion of hydrogen nuclei to form a helium atom. *

During the fusion process, energy is released.