A train travels a 400-km route and makes five stops in seven hours. Which equation is used to calculate the train’s average speed?


A.
Average speed = Sum of instantaneous speeds


B.
Average speed = Total distance x Total time


C.
Average speed = Total distance + Total time


D.
Average speed = Total distance ÷ Total time

Answers

Answer 1
The awnser is d. This is because say they where going 70 mph then it would take them 7 hours to go 490 miles.

Related Questions

There is a species of bamboo that can grow 36 inches per day. If a plant grew at this rate and was measured at 40 inches initially, how long (in days) would it take for the plant to grow to a height of 200 inches tall?

Answers

Answer:

It will take the plant [tex]4\frac{4}{9}[/tex] days or 4.44 days to grow to a height of 200 inches tall.

Explanation:

From the question, the rate at which the species of the bamboo tree grows is 36 inches per day.

To determine how long it would take a plant 40 inches tall initially to grow at this rate (that is, 36 inches per day) to a height of 200 inches.

This means we will calculate the number of days it will take the plant to grow additional 160 inches ( 200 inches - 40 inches) at this rate.

Now,

If the plant grows 36 inches in 1 day

then it will grow 160 inches in x days

x = (160 inches × 1 day) / 36 inches

x = 160 / 36

x = [tex]4\frac{4}{9}[/tex] days or 4.44 days

Hence, it will take the plant [tex]4\frac{4}{9}[/tex] days or 4.44 days to grow to a height of 200 inches tall.

One of the following statements is incorrect. (a) The car traveled around the circular track at a constant velocity. (b) The car traveled around the circular track at a constant speed. Which statement is incorrect and why?

Answers

Answer:

A

Explanation:

It is deemed to be incorrect because velocity deals with displacement. Or in more simple terms, distance in a specified direction.

While moving round the track, the direction keeps changing, so to say and the velocity vector changes constantly.

Speed on the other hand, is a scalar quantity that doesn't bother about nor depends on the direction being taken by the car.

that's all, I hope you understand it all

what is the mass of 1 litter of liquid in grams, if the density of liquids is 13.6g/ cm^3

Answers

Explanation:

1 L = 1000 cm³

m = ρV

m = (13.6 g/cm³) (1000 cm³)

m = 13,600 g

A doctor ran 100 meters in 20 seconds a duck slowly waddled 20 feet in 2 minutes some dude flew 100 miles in 2 hours Dave rolled down a hill he rolled 300 meters 30 seconds

Answers

Answer:

1. 50 m/s 2. 10 ft/min 3. 50 miles/hour 4. 10 m/s

Explanation:

We are required to calculate the speed in each instant

Since speed = distance/time,

1. For the doctor, speed = distance/time = 100 m/20 s = 50 m/s

2. For the duck, speed = distance/time = 20 feet/ 2 min = 10 ft/min

3. For the dude who flew, speed = distance/time = 100 miles/ 2 hours = 50 miles/hour = 50 mi/h

4. For Dave who rolled down the hill, speed  = distance/time = 300 metres/ 30 s = 10 metres/ second = 10 m/s

Oil dropping down the inner side of a tube confirms amine. This is what analysis ?

Answers

Answer:Qualitative

Explanation:

There is a hot iron nail and a liter of boiling water. Which one has heat energy? Why?
Guys plz answer it fast

Answers

The nail I believe because once the water heats up the nail it creates a reaction and once the nail gets red from being hot enough it creates energy

Answer:

Boiling Water.

Explanation:

Because there is still kinetic energy in the water. Thus it has heat energy.

The height of a model rocket h(t) is a function of the time since it was launched t

Answers

Answer:

0 [tex]\leq[/tex] t [tex]\leq[/tex] 40

Explanation:

Apex :)

Small blocks A and B are held at rest on a smooth plane inclined at 30° to the horizontal. Each is held in equilibrium by a force of magnitude 18 N. The force on A acts upwards parallel to a line of greatest slope of the plane, and the force on B acts horizontally in the vertical plane containing a line of greatest slope (see diagram). Find the weight of A and the weight of B. ​

Answers

Answer :

First of all, See the attachment for better understanding[tex].[/tex]

_________________________________

Weight of block A :

➝ mg sin30° = 18

➝ W (1/2) = 18

➝ W = 18×2

W = 36N

Weight of block B :

➝ N sin30° = 18

➝ (Mg cos30°) sin30° = 18

➝ W' (√3/2)(1/2) = 18

➝ W' (√3/4) = 18

➝ W' = 72/√3

W' = 41.61N

5.3 two 30 kg children in a 20 kg cart are stationary at the top of a hill. They start rolling down the 80 m tall hill and they are travelling at 30 km h-1 when they reach the bottom. how muvh work was done on the cart by friction during it's travel down the hill

Answers

Answer:

60008.4 J

Explanation:

The mass of each kid = 30 kg

mass of the cart = 20 kg

The speed of the cart down the hill = 30 km/hr = 30 x 1000/3600 = 8.33 m/s

The height of the hill = 80 m

The potential energy of the boys at the top of the hill = mgh

where

m is the total mass of the kids and the cart = (30 x 2) + 20 = 80 kg

g is the acceleration due to gravity = 9.81 m/s^2

h is their height above the ground = 80 m (on the top of the hill)

substituting, we have

potential energy PE = 80 x 9.81 x 80 = 62784 J

At an instance at the bottom of the hill

their kinetic energy = [tex]\frac{1}{2} mv^2[/tex]

where

v is their velocity = 8.33 m/s

m is their total mass = 80 kg

substituting, we have

kinetic energy KE = [tex]\frac{1}{2}*80*8.33^2[/tex] = 2775.6 J

Total work done on the cart is equal to the energy lost by the cart when it reached the bottom of the hill

work done by friction = PE - KE = 62784 - 2775.6 = 60008.4 J

A toy car is moving across a table with a velocity of 7.0 m/s and drives off the end. The table is 1.8 m tall. How long will the car be in the air before it crashes on the floor? a 0.6 seconds b 0.8 seconds c 0.4 seconds d 0.2 seconds

Answers

Answer:

Option D - 0.2 s

Explanation:

We are given;

Initial velocity; u = 7 m/s

Height of table; h = 1.8m

Now,since we want to find the time the car spent in the air, we will simply use one of Newton's equation of motion.

Thus;

h = ut + ½gt²

Plugging in the relevant values, we have;

1.8 = 7t + ½(9.8)t²

4.9t² + 7t - 1.8 = 0

Using quadratic formula to find the roots of the equation gives us;

t = -1.65 or 0.22

We can't have negative t value, thus we will pick the positive one.

So, t = 0.22 s

This is approximately 0.2 s

An airplane flies 700 miles with a tail wind in 2.0 hrs. If it takes 2.5 hrs to cover the same distance against the headwind, then what is the speed of the plane in still air? A).290mph B).315mph C).240mph D).330mph E).250mph

Answers

Answer:

B).315mph

Explanation:

Let the speed of the plane = p

Let the speed of the wind = w

Set up the system equation as;

                                     Relative V:               Time:                          Distance:

in wind direction:          p + w                         2                                  700

against wind:                 p - w                         2.5                                700

2(p + w) = 700

2.5(p - w) = 700

2p + 2w = 700

2.5p - 2.5w = 700

2.5  x:     5p + 5w = 1750

2  x:        5p - 5w = 1400

10p = 3150

p = 315 mph

Therefore, he speed of the plane in still air is 315 mph

                 

You are driving at 25 m/s with your cruise control on when you see a fallen tree in the road. It takes you 0.30 s to put on the brakes, your car decelerates at a rate of 5.0 m/s2, and the tree is 75 m ahead. Will you hit the tree? Choose the correct answer and reason below.

Answers

Explanation:

Given data

velocity v= 25m/s

The time it takes to put on brake t= 0.3s

the distance covered when the  brake was put on is

v=s/t

s= v*t

s= 25*0.3s

s= 7.5m

hence the distance covered is 7.5m

Also the rate of decrease in aceleration is 5m/s^2

we can also calculate the distance covered at this rate

v^2=u^2+2as

25^2= 0+2*5*s

625=10s

divide both sides by 10

s=625/10

s= 62.5m

The total  distance covered between putting on the brakes and decelareation is  7.5+62.5= 70m

Given that the tree is 75m ahead, the car would not hit the tree

Two jars are placed on a counter with a McDonald’s French fry inside. One has a lid, the other does not. They are left alone to see which one decays faster. After two days, the fry in the closed jar looks fresher.

The independent variable is?
The dependent variable is?
What should my conclusion be?

Answers

Your conclusion would be that the jar that’s lid is closed will be more fresh then the one with no lid

Which phrase is the best definition of matter

Answers

Answer:

Matter

Explanation:

Any type of material is a matter. It can be anything that occupies space and have mass. It is a composition of atoms which in term is made up of electrons, protons and neutrons. All particles in our universe is matter because everything has some mass and it occupies space.

Answer:

Anything that has mass and occupies space

Explanation:

Just took the test

Ed records the temperature of two pots of water. Pot X
has a temperature of 56 degrees Fahrenheit, and pot Y
has a temperature of 49 degrees Fahrenheit.
Answer is “ the water in pot x has more kinetic energy than the water in pot y”

Answers

Answer:

B on edgen

Explanation:

The water in pot X has more kinetic energy than the water in pot Y.

Answer:

the water in pot x has more kenetic energy.

Explanation:

not sure if its the answer. just found it on quizlet.

Two students want to determine if the acceleration of an object in free fall depends on the mass of the object. They conduct the following experiment to investigate this question: They drop a balled up sheet of paper (0.005 kg), a notebook (0.4 kg), and their physics book (5 kg) from a height of one meter. If air resistance is ignored, which of the following best predicts which object will experience the greatest acceleration?

Answers

Answer:

All the objects experience the same acceleration

Explanation:

According to Newton's law of universal gravitation, we have the gravitational force F given by the relation;

[tex]F=G \times \dfrac{M_1 \times m_{2}}{R^{2}}[/tex]

Where;

G = The universal gravitational constant

M₁ = The mass of the Earth

m₂ = The mass of the object in the Earths gravitational field

R = The radius of the Earth

Therefore, we have;

[tex]F= m_2 \times a = G \times \dfrac{M_1 \times m_{2}}{R^{2}}[/tex]

Which gives;

[tex]a = G \times \dfrac{M_1 }{R^{2}} \ which \ is \ a \ constant = 9.80665 \ m/s^2, \ known \ as \ g, \ which \ is \ \\the \ (acceleration \ due \ to \ gravity)\\[/tex]Therefore, based on the above calculation, all three object will have the same acceleration due to gravity, g, when air resistance is ignored.

What are the measurements that are used to

describe movement?

Answers

Answer: The SI unit

Explanation: The SI units are used to describe the distance an object moves

Machines
A pulley system having 5 pulleys is used to
raise a 450 N load. Find the Mechanical
advantage and hence the effort if the
efficiency is 75%.​

Answers

Explanation:

Hey there!!

Here, Given is,

Efficiency = 75%

VR = no. of pulleys = 5

Now,

[tex]effeciency = (\frac{ma}{vr} ) \times 100\%[/tex]

[tex]75\% = \frac{ma}{5} \times 100\% [/tex]

100% ma = 75%×5

[tex]ma = \frac{75\% \times5}{100\%} [/tex]

[tex]ma = \frac{375\%}{100\%} [/tex]

Therefore, MA is 3.75.

Hope it helps...

Answer:

MA=3.75

Explanation:Given that, E=75%, VR=no. of pulley=5

NOW,

E=(MA/VR)*100%

75%=(MA/5)*100%

MA=(75%*5)*100%

MA=375%/100%

∵MA=3.75

How can accuracy be limited?

Answers

Answer:

accuracy refers to the deviation of a measurement from a standard or true value of the quantity being measured

Push-ups and lifting weights are good examples of what type of physical activity?
Bone Strengthening Activities
O Muscle Strengthening Activities
Aerobic Activities

Answers

Answer:

I think it would be muscle

Explanation:

bones strengthened by calcium

aerobics is more of a gymnastical exercise

leaving a muscle strengthen

Answer:

Technically all 3

Explanation:

Include activities that make their hearts beat faster, build muscles (like climbing or doing push-ups), and strengthen bones (like running or jumping).

Traditional pushups are beneficial for building upper body strength. They work the triceps, pectoral muscles, and shoulders. When done with proper form, they can also strengthen the lower back and core by engaging (pulling in) the abdominal muscles. Pushups are a fast and effective exercise for building strength.Jun 22, 2018

Aerobic exercise (also known as cardiovascular exercise) builds your endurance. Anaerobic exercise typically means activities such as weightlifting and push-ups and sit-ups, which builds muscle and physical strength through short bursts of strenuous activity.

Calculate the workdone by a bricklayer who lifted cement block of mass 10kg from the floor to the height of 3cm g=9.8m​

Answers

Answer:

The work done is 2.94 Nm.

Explanation:

First, you have to find the force of a brick layer using the formula, Force = mass×gravity :

[tex]f = m \times g[/tex]

[tex]let \: m = 10,g = 9.8[/tex]

[tex]f = 10 \times 9.8[/tex]

[tex]f = 98N[/tex]

Given that the force of a brick layer is 98N. Next, you have to apply work done formula, Work done = force×distance :

[tex]w.d = f \times d[/tex]

[tex]let \: f = 98,d = 0.03m[/tex]

[tex]w.d = 98 \times 0.03[/tex]

[tex]w.d = 2.94Nm[/tex]

Lee skated 36 miles in 3h. What was the speed in which lee stated.

Answers

Answer: 12 mph

Explanation: 36 miles divided by 3 hours would be 12 mph

Solving with the Speed equation: v= d/t
(add to notes if desired)
3. Juan has ridden his bike a total distance of 20 km. If his average speed was 15km/h,
how much time did he ride for?
a)
What is given in the problem? (Circle)
b) What are we trying to find? (Square)
What will be the units to our solution?
d) Plug into the speed equation and solve.

Answers

Answer:

Explanation:

time= distance/speed

20km/ 15km/h

= 1 1/3 hours (4/3 in mixed fraction)

A baseball is thrown horizontally at 46 m/s. The ball slows down at a rate of 5 m/s2. How long
is the ball in the air before coming to rest?

Answers

Answer:

9.2 s

Explanation:

Using one of the equation of motion v = u + at where;

v is the final velocity = 0m/s (the ball comes to rest after throw)

u is the initial velocity = 46m/s

a is the acceleration = -5m/s² (the body decelerates)

t is the time taken by the ball in air

substituting the given parameters into the formula to get t, we will have;

0 = 46 +(-5)t

0 = 46 - 5t

subtract 46 from both sides

0-46 = 46-5t-46

-46 = -5t

Divide both sides by -5

-46/-5 = -5t/-5

t = 46/5

t = 9.2seconds

Hence it will take the ball 9.2seconds in the air before coming to rest.

Answer: 9.2sec

Explanation. 9.2sec

a dictatorship can also be a democracy ​

Answers

No, a dictatorship cannot also be a democracy. In a democracy, citizens have the power to chose who will be the political leaders for the country.

A liquid thermometer can be used to test for fevers. When body temperature increases,
the liquid inside the thermometer expands and rises to show a higher temperature reading. Which of the following explanations below best describes the
changes in thermal energy of the particles during this specific example of heat transfer?
A. The thermometer tip is heated by radiation from the person's body. The particles of the thermometer tip then transfer heat by convection through the
liquid inside of it. The particles inside the liquid then convect heat causing the warmer particles to slow down, expand, and rise.
OB. The thermometer tip is heated by conduction from the person's body. The particles of the thermometer tip then transfer heat by convection through the
liquid inside of it. The particles inside the liquid then convect heat causing the warmer particles to slow down, expand, and rise.
OC. The thermometer tip is heated by convection with the person's body. The particles of the thermometer tip then transfer heat by conduction with the
liquid inside of it. The particles inside the liquid then conduct heat causing the warmer particles to speed up, expand, and rise.
O D. The thermometer tip is heated by conduction with the person's body. The particles of the thermometer tip then transfer heat by conduction with the liquid
inside of it. The particles inside the liquid then convect heat causing the warmer particles to speed up, expand, and rise.
hey m

Answers

Answer:A

Explanation:

Hdjfjdjfjr

A liquid thermometer can be used to test for fevers. When body temperature increases, the liquid inside the thermometer expands and rises to show a higher temperature reading, the explanation that describes the change in the thermal energy,

The thermometer tip is heated by conduction with the person's body. The particles of the thermometer tip then transfer heat by conduction with the liquid inside of it. The particles inside the liquid then convect heat causing the warmer particles to speed up, expand, and rise.

What is thermal energy?

It can be defined as the form of the energy in which heat is transferred from one body to another body due to their molecular movements, thermal energy is also known as heat energy.

Conduction with the subject's body heats the thermometer's tip. The liquid inside the thermometer is subsequently heated by conduction between the particles of the thermometer tip. The warmer particles then accelerate, expand, and ascend as a result of the heat convecting through the liquid's particles.

Thus, the correct answer is option D.

Learn more about thermal energy from here

brainly.com/question/3022807

#SPJ2

A motorbike is traveling to the left with a speed of 27.0\,\dfrac{\text m}{\text s}27.0 s m ​ 27, point, 0, start fraction, start text, m, end text, divided by, start text, s, end text, end fraction when the rider slams on the brakes. The bike skids 41.5\,\text m41.5m41, point, 5, start text, m, end text with constant acceleration before it comes to a stop. What was the acceleration of the motorbike as it came to a stop?

Answers

Answer:

[tex]\frac{729\frac{m^{2} }{s^{2} } }{83m}[/tex]≈8.8[tex]\frac{m}{s^{2} }[/tex]

Explanation:

how fast does the light travel in a glass refractive index of 1.5?

Answers

Answer:

the light travels at a velocity of [tex]2\,\,10^8 \frac{m}{s}[/tex] in the glass

Explanation:

Recall that the refractive index of a material (n) is defined as the quotient between the speed of light in vacuum (c), and the speed of light in the medium (v). Therefore we can solve for the speed of light in the medium if we know the index of refraction it has:

[tex]n=\frac{c}{v} \\v=\frac{c}{n} \\v=\frac{3\,\,10^8}{1.5} \frac{m}{s} \\v=2\,\,10^8 \frac{m}{s}[/tex]

The period of a pendulum T depends on a constant g and the length of the pendulum ????in a relation given by

Answers

Answer:

The  relation is  [tex]T = 2\p \sqrt{\frac{l}{g} }[/tex]

Explanation:

Generally the mathematically relation showing the relationship between the period(T), the constant (g) and  the length(l) is

     [tex]T = 2\p \sqrt{\frac{l}{g} }[/tex]  

A hot–air balloon is moving at a speed of 10.0 meters/second in the +x–direction. The balloonist throws a brass ball in the +x–direction at a velocity of +4 meters/second with respect to himself. If the ball lands after 30 seconds, about how far does it land horizontally from the point at which it was released?
A. 120 meters
B. 125 meters
C. 300 meters
D. 420 meters

Answers

Answer:

Option (D) is correct.

Explanation:

The balloon lands horizontally at a distance of 420 m from a point where it as released.

Velocity of air balloon along +X axis =10 m/s

velocity of ball=4 m/s along + X axis

the velocity of balloon gets added to the velocity of ball. So the resultant velocity of the balloon=10+4 = 14 m/s

time taken= 30 s

The distance traveled is given by d= v t

d= 14 (30)

d= 420 m

Thus the balloon lands horizontally at a distance of 420 m from a point where it as released.

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