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A car of mass 400 kais sped up from 10m/s to 30m/s in a time of 15 seconds

What is the starting KE?
what is the ending KE?
what is the work done to speed up the car?
what is the power of watts?​

Answers

Answer 1

Explanation:

The initial kinetic energy [tex]KE_0[/tex] is

[tex]KE_0 = \frac{1}{2}mv_0^2 = \frac{1}{2}(400\:\text{kg})(10\:\text{m/s})^2[/tex]

[tex]\:\:\:\:\:\;\:= 2×10^4\:\text{J} = 20\:\text{kJ}[/tex]

The final kinetic energy [tex]KE[/tex] is

[tex]KE = \frac{1}{2}mv^2 = \frac{1}{2}(400\:\text{kg})(30\:\text{m/s})^2[/tex]

[tex]\:\:\:\:\:\:\:= 1.8×10^5\:\text{J} = 180\:\text{kJ}[/tex]

The work done W on the car is

[tex]W = \Delta{KE} = KE - KE_0[/tex]

[tex]\:\:\:\:\:\:\:= 180\:\text{kJ} - 20\:\text{kJ} = 1.6×10^5\:\text{J}[/tex]

The power expended P is

[tex]P = \dfrac{W}{t} = \dfrac{1.6×10^5\:\text{J}}{15\:\text{s}} = 10667\:\text{Watts}[/tex]

[tex]\:\:\:\:\:= 10.7\:\text{kW}[/tex]


Related Questions

3) A 60. kg person is in an elevator. The elevator starts from rest and then accelerates upwards at 2.0 m/s^2 for 4.0 seconds. Calculate the work done by the normal force on the person. *

Answers

Answer:

WD = 960 J

Explanation:

WD = work done (J)

F = force (N)

s = displacement (m)

m = mass (kg) = 60

a = acceleration (m/s²) = 2

t = time (s) = 4

u = initial velocity (m/s) = 0

The formulas or equations that are relevant ate:

WD = F × s

F = m × a

s = u + at

We want to find WD, so we need to now the force and the displacement (or distance);

We calculate force, in Newtons, with the formula F = ma:

F = 60 × 2

F = 120 N

We also need displacement, which get with the formula s = u + at:

s = 0 + 2(4)

s = 8 m

Now we have F and s, we can calculate WD:

WD = 120 × 8

WD = 960 J

Methodology:

Starting with what you want to find, in this case WD, list the formula/s you could use;

Then, identify the information you need for the formula and whether or not you are given that information;

Next, list the formulas for the information you don't have and once again, identify whether the information you are given is sufficient to use those formulas;

Once you can calculate all necessary information, then proceed to calculate the values and finally, the answer;

I suggest also keeping a list of all the variables as I've done at the top of my working so it is clear for you to see and use.

A man is whirling a 0.25 kg ball on a 1.5 m long string at 3 m/s. Find the centripetal acceleration of this ball.

Question 2 options:

0.5 m/s2

13.5 m/s2

6 m/s2

2 m/s2

Answers

The centripetal acceleration of this ball is equal to 12 [tex]m/s^2[/tex]

Given the following data:

Diameter = 1.5 mSpeed, V = 3 m/s.Mass = 0.25 kg

Radius = [tex]\frac{Diameter}{2} = \frac{1.5}{2} = 0.75 \;meters[/tex]

To find the centripetal acceleration of this ball:

The acceleration of an object along a circular track is referred to as centripetal acceleration.

Mathematically, the centripetal acceleration of an object is given by the formula:

[tex]A_c = \frac{V^2}{r}[/tex]

Where:

Ac is the centripetal acceleration.r is the radius of the circular track.

V is the velocity of an object.

Substituting the given parameters into the formula, we have;

[tex]A_c = \frac{3^2}{0.75}\\\\A_c = \frac{9}{0.75}\\\\A_c = \frac{9}{0.75}[/tex]

Centripetal acceleration = 12 [tex]m/s^2[/tex]

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science thanks sa points​

Answers

Answer: Are these free point?

Explanation:

The linear distance traveled by a wheel of radius 50cm after 99 complete revolutions is?

1)99m
2)210m
3)311
4)433

Answers

Answer:

3) 311 m

Explanation:

Circumference = 2πR = π m/rev

99 rev(π m/rev) = 99π m or about 311 meters

A gold doubloon 6.1 cm in diameter and 2.0 mm thick is dropped over the side of a pirate sheep.  When it comes to rest on the ocean floor at a depth of 770 m, how much has its volume changed?​

Answers

The definition of volume modulus and the variation of pressure with depth allows to find the result for the variation of the volume of the coin is:

ΔV = 2.15 10⁻⁸ m³

The pressure with the depth is given by the relation

         P = P₀ + ρ g h

Where P is the pressure, ρ is the density anf h depth.

The size of the bodies is determined by the distance of their atomic and molecular bonds, therefore the size of the bodies changes under external interations, in the case of hydrostatic pressure a constant called volumetric modulus is defined.

            [tex]B = - \frac{\Delta P}{\frac{\Delta V}{Vo} } \\\Delta V = - \frac{\Delta P }{B} \ V_o[/tex]

Where ΔP is the pressure change, V₀ and V are the volume change and the initial volume of the body, the negative sign is introduced so that the volumetric modulus is a positive quantity.

They indicate the diameter and thickness of the coin (d = 6.1 cm and e =0.20 cm) on the sea surface and the depth to which it is submerged

h = 770 m

Let's look for the volume of the coin.

          V₀ = π r² h = [tex]\pi \ \frac{d^2}{4} \ e[/tex]  

          V₀ = [tex]\pi \ \frac{0.061^2 }{4} \ 0.002[/tex]  

          V₀ = 5.84 10-6 m³

Let's find the pressure at the depth of y = 770 m,  the density of sea water is ρ = 1025 kg / m³, the pressure at the surface is the atmospheric pressure P₀ = 1 10⁵ Pa, the volumetric modulus of water is B = 0.21 10¹⁰ Pa.

          P = 1 10⁵ + 1025 9.8 770

          P = 1 10⁵ + 7,735 10⁶

          P = 7.84 10⁶ Pa

Let's calculate

          ΔV =[tex]- \frac{1 \ 10^5 - 7.84 \ 10^6 }{0.21 \ 10^{10}} \ 5.845 \ 10^{-6}[/tex]  

          ΔV = 2.15 10-8 m³

In conclusion using the definition of volume modulus and the variation of pressure with depth we can find the result for the variation of the volume of the coin is:

ΔV = 2.15 10-8 m³

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Some students conduct an experiment to prove conservation of momentum. They use two objects that collide Measurements
are taken before and after the collision.

Which two quantities will the students multiply together before and after the collision?


A. mass and velocity

B. distance and time

C. mass and acceleration

D. velocity and time

Answers

This question involves the concepts of the law of conservation of momentum, velocity, and mass.

The two quantities, the students should multiply before and after the collision are "A. mass and velocity".

According to the law of conservation of momentum, In an isolated system, the total momentum of the system before the collision is always equal to the total momentum of the system after the collision.

To prove the law of conservation of momentum, consider two balls of masses ‘m₁’ and ‘m₂’, moving with velocities ‘u₁’ and ‘u₂’, respectively, such that u₁ is greater than u₂. After some time, these balls collide with each other and their velocities become ‘v₁’ and ‘v₂’, respectively.

This situation is illustrated in the attached picture.

So, according to the law of conservation of momentum:

Total Momentum Before Collision = Total Momentum After Collision

m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

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Sorry this is a year late, but here it is for those of you who are stuck on the same thing.

======================================Proving Conservation of Momentum Quick Check - 5/5

NOTE: Please Check and Confirm That You Are On The Same Assignment with The Same Questions and Number of Questions. Thank You and Good Luck!

=======================================

1. Mass & velocity

2. The total momentum after the collision is the same as the total momentum before the collision.

3. 0.54 kg⋅m/s

4. The system has external forces, such as friction and air resistance, acting on it.

5. 3.0 m/s

Suppose a ball is thrown vertically upward (positive direction) from an initial height LaTeX: h_0 with initial velocity LaTeX: v_0. Find the position function LaTeX: s(t) of the ball after LaTeX: t seconds assuming the gravitational acceleration LaTeX: g is a positive constant pointing downward (negative direction).

Answers

After time t, the position function of the ball is determined as [tex]y(t) = h_0\ +\ v_0t \ - \ \frac{1}{2} gt^2[/tex]

The given parameters;

initial velocity of the ball, = [tex]v_0[/tex]initial position of the ball, = [tex]h_0[/tex]acceleration due to gravity, = g

The position function of the ball after time t, is calculated as follows;

[tex]y(t) = h_0\ +\ v_0t \ - \ \frac{1}{2} gt^2[/tex]

The negative sign of acceleration of due to gravity is because the ball is moving upward against gravity.

Thus, after time t, the position function of the ball is determined as [tex]y(t) = h_0\ +\ v_0t \ - \ \frac{1}{2} gt^2[/tex]

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What is sixth state of matter?

Answers

The fermionic condensate is a cloud of cold potassium atoms forced into a state where they behave strangely.

difference between speed and velocity​

Answers

Answer:

Speed is the time rate at which an object is moving along a path, while velocity is the rate and direction of an object's movement.

Explanation:

If the voltage across a 5-F capacitor is 2*e^-3
V find the current and the power

Answers

Answer correct in this picture………….

What is the relationship between balancing equations and the law of conservation of matter

Answers

Every chemical equation adheres to the law of conservation of mass, which states that matter cannot be created or destroyed. Therefore, there must be the same number of atoms of each element on each side of a chemical equation.

The center of gravity of a loaded truck depends on how the truck is packed. If it is 4.0 m high and 2.4 m wide, and its CG is 2.2 m above the ground, how steep a slope can the truck be parked on without tipping over

Answers

The slope of the road can be given as the ratio of the change in vertical

distance per unit change in horizontal distance.

The maximum steepness of the slope where the truck can be parked without tipping over is approximately 54.55 %.

Reasons:

Width of the truck = 2.4 meters

Height of the truck = 4.0 meters

Height of the center of gravity = 2.2 meters

Required:

The allowable steepness of the slope the truck can be parked without tipping over.

Solution:

Let, C represent the Center of Gravity, CG

At the tipping point, the angle of elevation of the slope = θ

Where;

[tex]tan\left(\theta \right) = \dfrac{\overline{AM}}{\overline{CM}}[/tex]

The steepness of the slope is therefore;

[tex]\mathrm{The \ steepness \ of \ the \ slope}= \dfrac{\overline{AM}}{\overline{CM}} \times 100[/tex]

Where;

[tex]\overline{AM}[/tex] = Half the width of the truck = [tex]\dfrac{2.4 \, m}{2}[/tex] = 1.2 m

[tex]\overline{CM}[/tex] = The elevation of the center of gravity above the ground = 2.2 m

[tex]\mathrm{The \ steepness \ of \ the \ slope}= \dfrac{1.2}{2.2} \times 100 \approx 54.55\%[/tex]

[tex]tan\left(\theta \right) = \mathbf{\dfrac{2.2}{1.2}} = \dfrac{11}{6}[/tex]

[tex]Elevation \ of \ the \ road \ \theta = arctan\left( \dfrac{6}{11} \right) \approx 28.6 ^{\circ}[/tex]

The maximum steepness of the slope where the truck can be parked is 54.55 %.

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Carbon tetrachloride (CCl4) is diffusing through benzene (C6H6), as the drawing illustrates. The concentration of CCl4 at the left end of the tube is maintained at 1.71 x 10-2 kg/m3, and the diffusion constant is 21.9 x 10-10 m2/s. The CCl4 enters the tube at a mass rate of 5.86 x 10-13 kg/s. Using these data and those shown in the drawing, find (a) the mass of CCl4 per second that passes point A and (b) the concentration of CCl4 at point A.

Answers

We have that for the Question "find (a) the mass of CCl4 per second that passes point A and (b) the concentration of CCl4 at point A."

Answers:

Mass of CCI_4 per second = [tex]5.86*10^{-13} kg/s[/tex] Concentration of CCI_4 = [tex]12.6*10^{-3}kg/m^3[/tex]

From the question we are told

The concentration of [tex]CCl_4[/tex] at the left end of the tube is maintained at 1.71 x 10-2 kg/m3, and the diffusion constant is 21.9 x 10-10 m2/s. The CCl4 enters the tube at a mass rate of 5.86 x 10-13 kg/s

 

A) the mass flow rate of CCI_4 as it passes point A is the same as the mass flow rate at which CCI_4 enters the left end of the tube

Therefore, the mass flow rate of CCI_4 at point A

=  [tex]5.86*10^{-13} kg/s[/tex]

B) From Fick's law

[tex]\deltaC = \frac{mL}{DAt}\\\\ Assume L = 5*10^{-3}, A = 3*10^{-4}\\\\\deltaC = \frac{5.86*10^{-13} * 5*10^{-3}}{21.9*10^{-10} * 3*10^{-4}}\\\\\deltaC = 4.46*10^{-3}kg/m^3[/tex]

Then,

[tex]Concentration = 1.71*10^{-2} - 4.46*10^{-3}\\\\= 12.6*10^{-3}kg/m^3[/tex]

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Describe the concept of energy quanta of EM radiation which was explained by Planck.

Answers

Answer:

Planck postulated that the energy of light is proportional to the frequency, and the constant that relates them is known as Planck's constant (h). His work led to Albert Einstein determining that light exists in discrete quanta of energy, or photons.

Explanation:

Answer:

Energy does not occur in continuous amounts but in discrete amounts described by:

E = N h ∨   where N is the number of quanta (energy units), ∨ the frequency of the energy, and h Planck's constant (6.63E-34 J-sec)

Accelerations are produced by

A. Masses
B.accelerations
C. Velocities
D.unbalanced, net forces

Answers

The correct answer is D.
Acceleration is produced by a net force on an object.

help :”)
a skydiver jumps out of a plane and falls for 45 seconds before deploying his parachute. how far did he fall?

Answers

Answer:

200 feet

Explanation:

is a fuel cell a primary or secondary cell

Answers

Answer:

Enrol in our 50 studyscore masterclass. Click here! Fuel cells are a type of primary cell in that they are not recharged, However, they are unique because they never run out, if the reactants are constantly supplied.

please help me
please help me
please help me​

Answers

Answer:

do it got a picture

on the edge

Explanation:

A small, free-to-rotate magnet is placed in a strong magnetic field. In what orientation will it come to rest

Answers

Answer:

South-North

Explanation:

Read the scenario below and answer the question that follows. Randall is hiring cooks for his restaurant. The first applicant is a handsome man with an average resumé and average job experience. The second applicant is a far less attractive man with a slightly above average resumé and above average job experience. Randall decides to hire the first applicant. Based on this information and on Randall’s decision, what might a psychologist conclude about Randall’s social perception? Randall has an unconscious assumption that attractive people are more competent. Randall has a unconscious assumption that unattractive people are bad cooks. Randall has a conscious assumption that attractive people make better cooks. Randall has a conscious assumption that unattractive people are more competent.

Answers

Randall has unconscious assumption that attractive people are more competent

Randall has an unconscious assumption that attractive people are more competent.

What is meant by assumption ?

The term assumption can be described as an unspoken premise that underlies the conclusion.

Here,

The capacity to accurately evaluate and draw conclusions about other individuals based on their overall physical appearance, verbal behaviour, and nonverbal attitudes is referred to as social perception.

Given that, for his restaurant, Randall is employing chefs. The first applicant is a dashing man with an average resume and career history. The second candidate is a far less appealing man with an average to slightly above average resume and work experience. Randall chooses to hire the first candidate.

This shows the social perception of Randall and his unconscious assumptions against unattractive people.

Hence,

Randall has an unconscious assumption that attractive people are more competent.

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A race car traveling at 100 m/s enters an unbanked turn of 400 m radius. The coefficient of (static) friction between the tires and the track is 1.1. The track has both an inner and an outer wall. Which statement is correct

Answers

Answer:

The race car will crash into the outer wall

Explanation:

max fr = μsN = 1.1 mg = 11 m

mv2/R = m(100)2/(400) = 25 m > fr

Which is the main gas that makes up the Earth's atmosphere?​

Answers

Answer:

78 percent nitrogen

Explanation:

I hope it's helpful for you

To get the dimmest bulbs with two batteries and two bulbs you would connect the batteries in ____ and the bulbs in ____.

Answers

Answer:

batteries in parallel connection and bulbs in serial connection

To get the dimmest bulb with two batteries and two bulbs you would connect the batteries in parallel and the bulbs in series.

What is Parallel and series circuits?

When two-terminal components and electrical networks that can be connected in series or parallel. This will result in two terminals in the electrical network, and may themselves participate in a series or parallel topology. When a two-terminal "object" is an electrical component or electrical network is a matter of perspective.

A circuit is said to be in series when the same current flows through all the components in the circuit where the current has only one path. A circuit is said to be parallel when there are multiple paths for the electric current to flow through it where the components which are part of the parallel circuit will have a constant voltage across all their ends.

Thus, to get the dimmest bulb with two batteries and two bulbs you would connect the batteries in parallel and the bulbs in series.

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What is discordant characteristic ?

Answers

[tex] \: \: \: \: [/tex]

being at variance; disagreeing

or incongruous: discordant opinions. disagreeable to the ear; dissonant; harsh.

hope it helps

[tex] \: \: \: \: \: [/tex]

dissimilar with respect to one or more particular characters

Does it appear that true average HAZ depth is larger for the high current condition than for the nonhigh current condition

Answers

Answer:

The data suggest that the true mean HAZ depth is larger when the current setting is higher.

a student lifts a toy car from a bench and places the toy car at the top of a slope describe an energy transfer that occurs when the student lifts the toy car from the bench and places the toy car at the top of the slope.

Answers

Answer:

Assuming there are no energy losses due to friction or drag, the gravitational potential energy will change into kinetic potential energy as the car reaches the bottom of the slope.

G.P.E = m*g*h

K.E = (m*v^2)/2

where

m = mass of toy car (kg)

g = gravity (m/s^2)

h = heigh of your car from the bottom (m)

v = velocity of the toy car as it reaches the bottom (m/s)

Equate K.E to G.P.E

G.P.E = K.E

m*g*h = (m*v^2)/2

make v the subject of the formula

v = (2*g*h)^(1/2)

Substitute g = 9.81 m/s^2 and h = 2m into the equation to get v

v = (2*9.81*2)^(1/2)

v = 6.264 m/s

calculate the surface area of a box whose mass is 200 kg and exerts a pressure of 100 Pascal on the floor.​

Answers

Answer:

Explanation:

If 2×2 is 4 so 1 kg can be 1 gram if it belive on it self some people change

How does friction help us in walking.​

Answers

Depending on the position and angle of our foot, this reaction contact force applied on our foot helps us to move forward as well as saves us from slipping and falling. This is how friction helps walking, in simple words.

73 ml of water is followed by 25 ml of juice. What is the percent strength of juice?

Answers

Total liquid: 73 + 25 = 98 ml

Percent juice = (25/98) x 100 = 25.5 %

An initially stationary object experiences an acceleration of 6 m/s2 for a time of 15 s. How far will it travel during that time?

Free-fall Acceleration is -10 m/s^2

Answers

Answer:

Explanation:

s = s₀ + v₀t + ½at²

s = 0 + 0(15) + ½(6)(15²)

s = 675 m

Not sure what the free fall acceleration is needed for, but if the object is dropped from a high enough point, it will travel in 15 seconds

s = ½10(15²) = 2250 m  if air resistance is ignored

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