if a runner travels 1600m in 420 seconds, her average speed is

Answers

Answer 1

Answer:

the answer is 3.8m/s in meters per second


Related Questions

What is the density of an object with a mass of 20 grams and a volume of 5 cm?

Answers

Answer:

4

Explanation:

Divide mass(m) by volume(v), you get density(D)

m/v=D

20/5=4

Particles in which state of matter are the most likely to interact with each other to cause a chemical reaction?

Answers

i think when particles are in the gas form they are most likely to cause a chemical reaction considering the fact that gas particles aren't very controllable and it would make sense that they would react unexpectedly

What is the force of gravity between two objects that are 4.0 m apart? The mass of the first object is 0.25 kg and the mass of the second object is 0.65 kg

Answers

Answer:

6.77 x 10^-13 Newtons

Explanation:

using the formula [tex]F= \frac{GMm}{r^2}[/tex]

where G is the gravitation constant which is 6.673 x 10^-11 N m2/kg2

M = mass of the first object which is 0.25 kg

m = mass of the second object which is 0.65 kg

and r is the distance between the objects which is 4 metres

Plugging our values in:

[tex]F\:=\:\left(6.673x10^{-11}\right)\frac{\left(0.25\right)\left(0.65\right)}{4^2}[/tex]

F = 6.77 x 10^-13 N

12. How many grams of beryllium are needed to produce 36.0 g of hydrogen? (Assume an excess of water.)
Be(s) + 2H, O() → Be(OH)2 (aq) +H,(g)
a
4.00 g
b. 36.0 g
c. 162 g
d 324 g

Answers

Answer:

Answer is: 162 g of beryllium.

Chemical reaction: Be + 2H₂O → Be(OH)₂ + H₂.

m(H₂) = 36,0 g.

m(Be) = ?

n(H₂) = m(H₂) ÷ M(H₂)

n(H₂) = 36,0 g ÷ 2 g/mol = 18 mol.

from reaction: n(Be) : n(H₂) = 1 : 1.

n(Be) = n(H₂) = 18 mol.

m(Be) = n(Be) · M(Be).

n(Be) = 18 mol · 9 g/mol = 162 g.

Answer:

Answer is: 162 g of beryllium.

Chemical reaction: Be + 2H₂O → Be(OH)₂ + H₂.

m(H₂) = 36,0 g.

m(Be) = ?

n(H₂) = m(H₂) ÷ M(H₂)

n(H₂) = 36,0 g ÷ 2 g/mol = 18 mol.

from reaction: n(Be) : n(H₂) = 1 : 1.

n(Be) = n(H₂) = 18 mol.

m(Be) = n(Be) · M(Be).

n(Be) = 18 mol · 9 g/mol = 162 g.

help guysssssssssssssssssssssssssssss

Answers

Answer: D) Earthquake

I hope this helps, and Happy Holidays! :)

Answer:  Earthquakes

Explanation: Earthquakes impact rupture breaks in the ground, landslides, avalanches, fires, tsunamis, property damage, and loss of life.

a car travels 200km in 3.0 hours. Determine the average velocity of the car

Answers

Answer:

66.67 km/hr

Explanation:

The average velocity of the car can be found by using the formula

[tex]a = \frac{d}{t } \\ [/tex]

d is the distance

t is the time taken

From the question we have

[tex]a = \frac{200}{3} \\ = 66.66666...[/tex]

We have the final answer as

66.67 km/hr

Hope this helps you

A fireboat is to fight fires at coastal areas by drawing seawater with a density of 1030 kg/m3 through a 10-cm-diameter pipe at a rate of 0.04 m3/s and discharging it through a hose nozzle with an exit diameter of 5 cm. The total irreversible head loss of the system is 3 m, and the position of the nozzle is 3 m above sea level. For a pump efficiency of 70 percent, determine the required shaft power input to the pump and the water discharge velocity.

Answers

Answer:

50.93 m/s

199.5 kW

Explanation:

From the question, the nozzle exit diameter = 5 cm, Radius= diameter/2= 5cm/2= 2.5cm. we can convert it to metre for unit consistency= (2.5×0.01)=

0.025m

We can calculate the The cross sectional area of the nozzle as

A= πr^2

A= π ×0.025^2

= 1.9635 ×10^- ³ m²

From the question, the water is moving through the pipe at a rate of 0.1 m /s , then for the water to move through it at a seconds, it must move at

(0.1 / 1.9635 ×10^- ³ m²)

= 50.93 m/s

During the Operation of the pump, the Dynamic energy of the water= potential energy provided there is no loss during the Operation

mgh = 1/2mv²

We can make "h" subject of the formula, which is the height of required head of water

h = (1/2mv²)/mg

h= v² / 2g

h = 50.93² / (2 ×9.81)

h = 132.21m

From the question;

The total irreversible head loss of the system = 3 m,

the given position of nozzle = 3 m

the total head the pump needed=(The total irreversible head loss of the system + the position of the nozzle + required head of water )

=(3 + 3 + 132.21m)

=138.21m

mass of water pumped in a seconds can be calculated since we know that mass is a product of volume and density

Volume= 0.1m³

Density of sea water=1030 kg/m

(0.1 m^3× 1030)

= 103kg

We can calculate the Potential enegry, which is = mgh

= (103 ×9.81 × 138.21)

= 139651.5 Watts

= 139.65kW

To determine required shaft power input to the pump and the water discharge velocity

Energy= efficiency × power

But we are given efficiency of 70 percent, then

139651.5 Watts = 0.7P

=199502.18 Watts

P=199.5 kW

Therefore, the required shaft power input to the pump and the water discharge velocity is 199.5 kW

41. What effects the efficiency of a pulley?

a. the type of rope or cable

b. the way the wheel turns

c. the length of the rope

d. how big the wheel is

e. only a and be

f. all of the above

Answers

Answer:

e. only a and b

Keith has been using a software application for a year on his home computer. A new version of the application was recently released. Keith’s license has a term of two years and entitles Keith to upgrade his application to a new version within the term. What type of license does the application have?

Answers

Answer:

d license with maintenance .

Explanation:

just took this test. :)

Why doesn’t the force you exert when sitting on a chair cause the chair to move?

a. The floor exerts a balancing force on the chair.
b. The floor exerts too much force on the chair
c. The floor exerts an unbalancing force on the chair.
d. The floor exerts no force on the chair.

Answers

Answer:

the answer is A

Explanation:

2. An 873 kg dragster accelerates at a rate of 44.6 m/s during a race.
a. What is the magnitude of the net force exerted on the dragster during this time?
Known (Given):
=
Unknown:
Fnet =
Equation:
Fret=ma (or m*a)
Solution:

Answers

Answer:

38,673.9N

Explanation:

According to newton's second law:

Force = mass * acceleration

Given

Mass = 873kg

acceleration = 44.66m/s²

Magnitude of the force is expressed as;

F = ma

F = 873 * 44.6

F = 38,673.9N

Hence the magnitude of the net force exerted on the dragster during this time is 38,673.9N

How do ions help your brain?

Answers

Generally speaking, negative ions increase the flow of oxygen to the brain resulting in higher alertness, decreased drowsiness, and more mental energy.
So, when talking about ions it’s very important to understand everything around..you consume everything you breathe in. It can effect you in many ways!!! Ok starting off, negative ions can help with more alert and stamina. These traits include longer and higher alertness, the decreasing of drowsiness when doing activities, and more mental energy!

1. Four identical elephants are at different heights. If your physics teacher
asked you which of the following elephants has the greatest amount of
potential energy, what will be your answer? And why?

Helpppp:(((((​

Answers

Elephant D does because it is at the highest height and can exert a greater amount of force leading to a greater amount of energy

D. Ampere
A screw of length 5 cm enters totally into a wooden block after 25 turns. What is the pitch of the
screw?
A. 0.1 cm
B. 0.2 cm
C. 0.4 cm
D. 0.5 cm

Answers

Features of the mobilization monkey

Answer:

0.5

Explanation:

u must simplyfiy

Write two forms of mechanical energy

Answers

kinetic gravitational

When a person strikes and lights a match, potential energy in the match is transformed into which types of energy?

electrical and thermal
thermal and radiant
radiant and nuclear
nuclear and kinetic
hurry brainliest ill give 49 points

Answers

Answer:

Radiant and thermal

Explanation:

Electrical and thermal don't make sense because you are not using electricity to light the match. Radiant and nuclear is not right because you are not using nuclear energy to light the match. Nuclear and kinetic isn't right because you are using kinetic and you are not using nuclear energy.

Answer:

answer is B. thermal and radiant

Explanation:

just got it right on edge

A 35kg cannonball sits at rest on a flat level surface. What is the normal force exerted on the cannon ball. Use -9.8 m/s2 for acceleration due to gravity.

A. -343N

B. 44.8N

C. 25.2N

D. 343N

Answers

Answer:

a) N = 343 [N]

Explanation:

We must remember Newton's third law, which tells us that the force acting on a body is equal to the normal reaction force of equal magnitude but acting in the opposite direction.

[tex]N=m*g[/tex]

where:

m = mass = 35 [kg]

g = gravity acceleration = 9.81 [m/s²]

[tex]N = 35*9.8\\N= 343 [N][/tex]

A 10 N force and an 18 N force act in the same direction on an object. What is the net force on the object?

Answers

Answer:

28 N

Explanation:

From the question given above, we were told that 10 N force and 18 N force act in the same direction on the object.

The net force acting on the object can be obtained by simply adding both forces together since they both act on the object in the same direction. This is illustrated below:

Force 1 (F₁) = 10 N

Force 2 (F₂) = 18 N

Net force (Fₙ) =?

Fₙ = F₁ + F₂ (since they both act in the same direction)

Fₙ = 10 + 18

Fₙ = 28 N

Therefore, the net force acting on the object is 28 N.

A 20 kg mass is hanging on one side of a pulley and a 5 kg mass is hanging on the other. Determine the acceleration of each mass.

Answers

Answer:

i believe it's 7

Explanation:

Question 1 of 25
A bookcase has a mass of 37 kg. What is the weight of the bookcase?

Help please

Answers

answers

81.6 pounds rounded or just 81.571 if it needs to be exact

66.13 pounds rounded

I’ll give BRAINLIEST to the person that answer this questions (and if they right) :
People who are REACTIVE are like _____ , and PROACTIVE people are like ____.
A. A bottle of water and a bottle of soda
B.A bottle of soda and a bottle of water
C.None of the above
D.All of the above

PROACTIVE people make their choices based on ____.
A.Reasoning
B.Anger
C.Feelings
D.what others say

What is the opposite of being REACTIVE?
A.Being proactive
B.Being inactive
C.Being semi-active
D.All of above

Habit 1:Be proactive means:
A.thinking everyone can win
B.Take responsibility for your own life
C.Become a professional athlete
D.Doing something right away

Answers

It’s c for the first one hope this help

1: C

2: C

3: A

4: B

there you go

This image shows flashlight beams reflecting off a mirror from
different angles. Based on the angles of reflection, choose all pairs of
light rays that correctly match incoming light beams with their
reflected light beams,



Question 2. Based on the image and the angles of reflection shown witch statement is true.

A) When a light ray strikes a mirror, it randomly scattered.

B) light is absorbed by mirrors and reflected directly upwards.

C) light travels in a straight line until lit strikes an object

D) light is reflected back to its source when it strikes an object

Answers

Hey I'm working on this test right now, did you ever get the answers?

a 50.0kg skydiver experience a 740newton air resistance force determine her acceleration please help asap​

Answers

Answer:

a = - 5 [m/s²].

Explanation:

To solve this problem we must use Newton's second law, which tells us that the sum of forces on a body is equal to the product of mass by acceleration.

∑F = m*a

where:

F = resultant force [N] (units of Newtons)

m = mass = 50 [kg]

a = acceleration = 9.81 [m/s²]

For this particular problem, the only forces acting are the force of gravity acting down with negative sign, while the force of air opposes the fall, in this way it is positive.

[tex]f_{air}-F_{grav}=-m*a[/tex]

As the movement is pointing down the acceleration will be taken as negative.

[tex]740-(50*9.81)=-50*a\\740-490.5 = -50*a\\249.5 = -50*a\\a = - 5 [m/s^{2} ][/tex]

We should note that in this case, the acceleration has a negative sign, this means that the force of the air makes the skydiver move upwards

what is the kinetic energy of a 1 kilogram ball thrown into the air with an initial velocity of 30 m/s

Answers

Explanation:

KE = 1/2 MV ^2

KE = 1/2 * 1 * 30 ^2

KE= 1/2 * 1 * 900

KE = 450 kg m^2/ s^2

please mark me as a brainelist

Answer:

the above pic will help

I have done it in word

I hope it helps mate

mark me brainliest plsss

I will always help you understanding your assingments

have a great day

#Captainpower:)

What two things does force depend on​

Answers

Answer:

When dealing with the force of gravity between two objects, there are only two things that are important – mass, and distance or (acceleration)

Explanation:

Which two forces act over very small distances

Answers

Explanation:

There are three fundamental forces that act at a distance. They are gravitational, electromagnetic and nuclear forces.

hope it helps!

What do we know about the relative strength of the electric field around each object?

Answers

Answer:

A charged object in an electric field experiences a force due to the field. The electric field strength, E, at a point in the field is defined as the force per unit charge on a positive test charge placed at that point.

Explanation:

Find the displacement of the object moving at v= -2 m/s for t=5s

Answers

Answer:

d = - 10 [m]

Explanation:

We must remember that speed is defined as the relationship between the displacement in a given time. In this way, we can propose the following equation.

[tex]v = d/t[/tex]

where:

v = velocity = 2 [m/s]

d = displacement [m]

t = time = 5 [s]

Now replacing:

[tex]d=-5*2\\d=-10[m][/tex]

A supply plane drops a package to the ground for stranded campers below. After falling for 8.14 seconds, the package will have a downward velocity of 80.79 m/s. How high was the plane when it dropped the package?

Answers

Answer:

333 m

Explanation:

The following data were obtained from the question:

Initial velocity (u) = 0 m/s.

Time (t) = 8.14 s.

Final velocity (v) = 80.79 m/s.

Acceleration due to gravity (g) = 9.8 m/s²

Height (h) =?

v² = u² + 2gh

80.79² = 0 + (2 × 9.8 × h)

6527.0241 = 0 + 19.6h

6527.0241 = 19.6h

Divide both side by 19.6

h = 6527.0241 / 19.6

h = 333 m

Thus, the plane was at a height of 333 m when the package was dropped.

These the flow of electrons (the current) and where some of the electrons' energy gets converted into heat. (Lessons 5.01-5.03) electric currents Insulators Resistors Conductors​

Answers

Answer: The answer is resistors

Explanation: I just took the unit test and it was correct

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