Lenny wrote the steps he used to find the mass of an object with 400 J of energy moving at a velocity of 8 m/s.
1. Find the square of 8 m/s, which is 64 m2/s2.
2. Divide kinetic energy, 400 J, by 64 m2/s2, which is 6.25 J per m2/s2.
3. Divide 6.25 J per m2/s2 by 2 to get a mass of 3.125 kg.

Which best describes Lenny’s error?

A. In Step 1, he should have found the square root of 400 J instead of squaring 8 m/s.
B. In Step 1, he should have multiplied 8 m/s by 2 instead of squaring it.
C. In Step 2, he should have divided 64 m2/s2 by 400 J instead of dividing 400 J by 64 D. m2/s2.
In Step 3, he should have multiplied 6.25 J per m2/s2 by 2 instead of dividing it by 2.

Answers

Answer 1

Answer:

In Step 3, he should have multiplied 6.25 J per m2/s2 by 2 instead of dividing it by 2.

Explanation:

Answer 2

D. In Step 3, he should have multiplied 6.25 J per m2/s2 by 2 instead of dividing it by 2.

What is Kinetic energy?

The energy that it possesses due to its motion. It is defined as the work needed to accelerate a body of a given mass from rest to its stated velocity.

According to the question,

The object posses an kinetic energy,

Given Mass of an object = 400 J

Energy moving at a velocity= 8 m/s.

[tex]E_k =\frac{1}{2} mv^2\\\\=400J = \frac{1}{2} *m(8)^2\\\\\\=\frac{400J}{64m^2/s^2} = \frac{1}{2}*m\\ \\ =6.25 *2 = m\\\\=12.25 kg[/tex]

Hence,

In the step 3 ,he should have multiplied 6.25 J per m²/s² by 2 instead of dividing it by 2.

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Related Questions

A 80.0kg football player running at 12.5 m/s North runs into a 120.kg player running South. The 120.kg player grabs the other one so they move together at -4.50m/s. What was the velocity of the 120.kg player?

Answers

Answer:

p=-540kg•m/s

Explanation:

because I used a calc

Does anybody know anything about speed and velocity? im hella stuck.

Answers

Answer:

lm.ao i was stuck too when i was on that

Explanation:

what u need to know sis?

speed, being a scalar quantity, is the rate at which an object covers distance. The average speed is the distance (a scalar quantity) per time ratio. Speed is ignorant of direction. On the other hand, velocity is a vector quantity; it is direction-aware. Velocity is the rate at which the position changes.

An object at rest has equal forces acting on it. This can be described as a(n) _____________ force.

gravity
unbalanced
balanced
physical

Answers

Answer. Balanced
Explanation. Balanced forces provides an equal reaction to each action. For example, if you push on a wall, your hand isn’t going to go through. This is because the push is equal to the pull and the forces are balanced.
Hope this helped, let me know if it’s correct so others can use it :)
Good luck

A physical quantity that has both magnitude and a direction is the definition of

Answers

Explanation:

Vector, in physics, a quantity that has both magnitude and direction. It is typically represented by an arrow whose direction is the same as that of the quantity and whose length is proportional to the quantity's magnitude.

A Galapagos tortoise weighs 59 Newtons (on Earth). What is its mass in kilograms?

Answers

Answer:

It is 6.02 kilograms.

Explanation:

One kilogram is equal to 9.81 Newtons. To convert Newtons to Kilograms,divide by 9.81. For instance, 20 Newtons would be equivalent to 20/9.81 or 2.04 kilograms

3
Select the correct answer
A kilogram is an si unit. Which quantity might you measure in kilograms?
О А.
temperature
B.
mass
C. length
D.
electric current
Reset
Next

Answers

Answer:

mass

.

Explanation:

Answer:

It would be B

Explanation:



If this woman pushes down on her lever with a force of 25N and the rock moves with a
force of 100N, what was the mechanical advantage?

Answers

Answer:

0.25

Explanation:

plz help i beg, veryyy confused :)

Answers

Displacement is distance in one particular direction. Distance is the route taken without worrying about the direction.
To find the displacement draw a straight line from the start point to the end point. Measure the length and use the scale to find the real distance.
Ask me if you need more help.

Which two quantities can be used to describe motion?
A. Displacement and velocity
B. Displacement and weight
C. Speed and weight
D. Velocity and mass

Answers

Displacement and velocity are the two quantities that can be used to describe motion.

What are the quantities used to describe motion?

Motion is defined in terms of displacement, time, velocity, and acceleration. Velocity is defined as the rate of change of displacement whereas acceleration is defined as the rate of change of velocity.

Most of the quantities used to describe motion can be categorized as vectors or scalars. A vector is a quantity that is described by both magnitude and direction whereas a scalar is a quantity that is described by magnitude only.

The motion of an object can be defined as Uniform motion which means equal distance is covered in equal time and a non-uniform motion means an equal distance is covered by an object in equal intervals of time.

So we can conclude that option A is the correct answer.

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a book has a mass of 50 kg and an acceleration of 5 m/s/s. what is the force of the book
help asap

Answers

Answer:

250 N

Explanation:

F=ma

F=50 kg(5 m/s/s)

F=250 N

Answer:

F=250N

Explanation:

I hope this helps you out and if your feeling generous plz mark brainliest it helps me a lot thank you:)

What is the velocity of a car that travelled a total of 75 km north in 1.5 hrs?

Answers

V=d*t
Since d=75km=75000m
t=1.5h=3600*1.5= 5400s
=>V=75000*5400
=405000000m/s=4.05*10^8m/s

what is the speed of an object that travels 40m in 2 s?

Answers

I think the answer is 20m/s because you have to divide distance into time to get speed ☺️

Contact forces & friction. Please help!!! (20 points & brainliest!)

Answers

Let w denote the weight of the box, n the magnitude of the normal force (the sheet pushing up on the box), k the magnitude of the kinetic friction force, and µ the coefficient of kinetic friction.

The kinetic friction force doesn't kick in until the sheet is tilted at an angle θ₂. Since the box is sliding down at constant speed, it's in equilibrium and the forces acting on it sum to 0.

In the horizontal direction (literally left-and-right, parallel to the ground and not the sheet), we have only the horizontal components of the friction and normal forces to worry about, so that [tex]\mathbf n_x+\mathbf f_x=\mathbf0[/tex], which reduces to

f cos(θ₂) + n cos(90º + θ₂) = 0

(where we take the right to be positive and left to be negative)

Recall that cos(90º + x) = -sin(x) for all x, and that the friction force is proportional to the normal force by a factor of µ. This gives

µ n cos(θ₂) - n sin(θ₂) = 0

Solve for µ :

µ n cos(θ₂) = n sin(θ₂)

µ = sin(θ₂) / cos(θ₂)

µ = tan(θ₂)

A boy runs 400m at an average speed of 4.0m/s he runs the first 200m in 40 s how long does he take to run the second 200m?

Answers

if he runs at the same speed he will cover next 200m in 40s
that is at the average of 4.0m

if the boy runs  400m at an average speed of 4.0m/s he runs the first 200m in 40 at the same speed he will cover next 200m in 40 s  and the the average speed is  of 4.0m

What is angular speed ?

Angular speed is a measures of speed of how fast the central angle of a rotating body changes with respect to given time

It mainly implies how quickly the object is  rotating means it is described as the change in the angle of the object per unit of time.

To calculate the speed the value of  angular speed are needed thus  angular speeds formula is used to calculate the distance traveled by an object in terms of rotation and revolutions per unit of time.

The unit of angular speed of an object is denoted as radian per second and Both angular speed, angular velocity are calculated by using the same formula.

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8. An object accelerates 12.0 m/s2 when a force of 6.0 newtons is applied to it. What is the mass of the object? ___________________________

Answers

Answer:

Mass of object is 0.5kg

Explanation:

Given the following data;

Force = 6N

Acceleration = 12m/s²

Mass =?

Force is given by the multiplication of mass and acceleration.

Mathematically, Force is;

[tex] F = ma[/tex]

Where;

F represents force.

m represents the mass of an object.

a represents acceleration.

Making mass (m) the subject, we have;

[tex]Mass (m) = \frac{F}{a}[/tex]

Substituting into the equation;

[tex]Mass (m) = \frac{6}{12}[/tex]

Mass, m = 0.5kg.

Therefore, the mass of the object is 0.5kg

A car is driving at 35 m/s. It decides to accelerate at 4.5 m/s2 for 3 seconds. How fast is it now moving?
Please show work even if you are an online student. I know it takes time, but I promise it is worth it.
I have included the units in the answer already. Please only put the number round all answers to 2 decimal places
if possible.
final velocity =
m/s
Blank 1
Next Page
6
? ? ?

Answers

Answer:

48.5

Explanation:

vf = vi + at

vf = 35 + 4.5(3)

vf = 35 + 13.5

vf = 48.5 m/s

b) A stone is dropped from the roof of a four storey building. The height of
each storey is 4.9m . Taking g =9.8m/s2 , calculate the velocity with
which the stone will hit the ground.

Answers

Answer:

9.8m/s

Explanation:

Given,

distance of each storey () = 4.9m

distance of 4 storey (s) = 19.6m

acceleration due to gravity (g) = 9.8 m/s^2

time given (t) = ?

velocity = (?)

initial velocity (u) = 0 {due to fall from certain height}

using formula,

s = ut + 1÷2at^2

s = 0 + 9.8÷2×t^2

19.6×2÷9.8 = t^2

4 = t^2

t = 2

now,

velocity ( v )= s ÷ t

v = 19.6 ÷ 2

v = 9.8 m/s

ans

An apple suddenly drops a distance of 3.2 m from a tree. If the acceleration due to gravity is 9.8 m/s2, how long does it take the apple to reach the ground?. Give your answer to two decimal places.

Answers

Answer:

0.33 seconds

Explanation:

The time taken by the apple to reach the ground will be 0.8 seconds.

What is velocity?

The velocity of an object is the ratio of its travel distance over a given amount of time. The magnitude and direction are both necessary for the velocity because it is a vector quantity.

Given that an apple suddenly drops a distance of 3.2 m from a tree. If the acceleration due to gravity is 9.8 m/s². The time taken by the apple to reach the ground will be calculated by the formula below:-

Time = √ ( 2s)/g)

Time = √ ( 2 x 3.2 )/9.8)

Time = 0.8 second

As a result, it will take the apple 0.8 seconds to reach the ground.

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Do Now: You are asked to go to downtown Newark and pick up a small bag of materials for a grant project. Pay is $25. The materials will be delivered to Room 224, 2nd floor in Barringer High School. Create a numbered procedure, a list of steps that you will take to pick up and deliver the materials. Click for Example

Answers

Answer:

sorry im not in physics

Explanation:

What is the SI unit used to measure the temperature of a substance?
A. degree Celsius
OB
degree Fahrenheit
gram
OD
kelvin
ОЕ.
mole
Reset
Next

Answers

Answer:

Kelvin

Explanation:

Kelvin is the universal and scientific unit for temperature as Celsius and Fahrenheit temperatures we use in everyday situations

Solve.

h ÷ 4 = 9

h =

Answers

the answer is 36 because you multiply 4 on each side to cancel the divide by 4 out

help me please asap :(

Answers

17. a
18. c
19. a
20. c
21. c

Determine the initial velocity of a marble that lands 1.8m away from a tabletop that is 0.8m from the ground.
Acceleration due to gravity = 9.85
0 2.25 m/s
2.6 m/s
0 1.8 m/s
4.5 m/s

Answers

Answer:

4.5 m/s

Explanation:

[tex]s_x[/tex] = Horizontal displacement = 1.8 m

[tex]s_y[/tex] = Vertical displacement = 0.8 m

[tex]u_x[/tex] = Horizontal velocity

g = Acceleration due to gravity = [tex]9.81\ \text{m/s}^2[/tex]

t = Time taken to fall down

[tex]s_y=u_yt+\dfrac{1}{2}gt^2\\\Rightarrow 0.8=0+\dfrac{1}{2}\times 9.8\times t^2\\\Rightarrow t=\sqrt{\dfrac{2\times 0.8}{9.8}}\\\Rightarrow t=0.4\ \text{s}[/tex]

[tex]s_x=u_xt+\dfrac{1}{2}a_xt^2\\\Rightarrow 1.8=u_x\times 0.4+0\\\Rightarrow u_x=\dfrac{1.8}{0.4}\\\Rightarrow u_x=4.5\ \text{m/s}[/tex]

The initial velocity of the marble is 4.5 m/s.

33. A zebra is at rest 60 m away from a charging lion
running at 20 m/s. If the zebra accelerates at 4
m/s2, will the lion catch it?

Answers

Answer:

the lion will miss the zebra by 3 meters

Explanation

The zebra has gone 23.75m after 5 seconds

and the lion can only go 20 m/s

The lion can not catch zebra.

A diagram is attached below which describe situation of question.

The speed of Zebra is,

      [tex]v=u+at=0+4t=4t[/tex]

Where u is initial speed of zebra.

The speed of lion is 20m/s.

The lead in speed by lion for every second is [tex](20-4t)[/tex].

             [tex](20-4t)*t=60\\\\20t-4t^{2}=60\\ \\t^{2}-5t+15=0\\ \\t=\frac{5\pm\sqrt{(-35)} }{2}[/tex]

Here time is imaginary.

Therefore, The lion can not catch zebra.

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If a 25 kg object is moving at a velocity of 5 m/s, the object has energy​

Answers

Answer:

Since the KE is proportional to velocity squared, if you increase the KE by a factor of

2

, you increase

v

by a factor of

2

2

=

4

Detailed explanation :

25

=

0.5

m

(

5

2

)

Find

m

:

25

=

25

m

2

m

=

2

Hence the new KE:

KE

=

0.5

2

10

2

KE

=

100

J

What is the magnitude of the resultant vector? Round your answer to the nearest tenth

Answers

Answer:13.9 on edgy I just did it

Explanation:

Answer:

13.9

Explanation:

just did it

what body part plays a strong role in releasing power​

Answers

Answer:

I think your bones, muscles, and joints your welcome :)

Explanation:

The mass of an unidentified rock is 15.5 grams. Students determine the volume of the rock by placing the rock in a cylinder with water. The students calculate the density of the rock. They determine the identity of the rock based on the density ranges in the table.

The students most likely have which type of rock?

Coal
Dolomite
Peridotite
Sandstone

Answers

Answer:

this density is in the range of Peridotite type rocks

Explanation:

In this graduated cylinder exercise we can directly read the volume of the rock

         V = (35 - 30) cm³

          V = 5 cm³

They also indicate the mass of the rock

          m = 15.5 gr.

Density is defined as the ratio of mass to volume

          ρ = 15.5 / 5

          ρ= 3.1  gr /cm³

When checking the attached table this density is in the range of Peridotite type rocks

The type of rock the students mostly like have is Peridotite.

We'll begin by calculating the volume of the rock. This can be obtained as follow:

Volume of water = 30 mL

Volume of water + rock = 35 mL

Volume of rock =?

Volume of rock = (Volume of water + rock) – (Volume of water)

Volume of rock = 35 – 30

Volume of rock = 5 mL

Finally, we shall determine the type of rock the students have by calculating the density of the rock. This can be obtained as follow:

Volume of rock = 5 mL = 5 cm³

Mass of rock = 15.5 g

Density of rock =?

Density = mass / volume

Density of rock = 15.5 / 5

Density of rock = 3.1 g/cm³

Comparing the density of the rock (i.e 3.1 g/cm³) with those given in table above, we can conclude that the rock is peridotite

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1
Two beaker of water A and B , initially are at the same temperature.The temperature of the

water in beaker A is increased by 10F and the temperature of water in beaker B is increased

10 K. After these temperature change,which beaker of water has the higher temperature?​

Answers

Answer :

beaker A , it is because the temperature increases is higher than beaker B.

Formula

(10°F − 32) × 5/9 + 273.15 = 260.928K

10 degrees fahrenheit = 260.928 kelvins

Formula

(10K − 273.15) × 9/5 + 32 = -441.7°F

10 kelvins = -441.67 degrees fahrenheit

beaker A , 10°F = -12.222 °C

beaker B , 10k = -263.15 °C

 

Beaker A of water will have a higher temperature than the temperature of beaker B.

How to change the temperature from Fahrenheit to Celcius?

To convert the temperature Fahrenheit to Celsius formula is used from the scale Fahrenheit to Celsius. Both scales provide a way to measure the object’s hotness and coldness and are used to measure the temperature. The symbol used to express Fahrenheit is °F while the symbol used for Celsius is °C.

The formula used to change the temperature from Fahrenheit to Celsius as follows:

°C = (°F- 32)5/9

The temperature of beaker A  is increased by 10°F. So the change in temperature in the Celcius scale is :

T(°C) = (10- 32)5/9

T(°C) =  -12.22°C

The temperature of beaker B  is increased by 10 K, then the temperature in Celcius is:

T(°C) = 10 - 273.15

T(°C) = - 263.15°C

Therefore, the temperature of beaker A will be higher after these changes if initially, both are at the same temperature.

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PLEASE SAY IM RIGHT AGAIN?

Answers

I believe it’s the scientific revolution
Hope this helps :)
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