Kinematics
29. A car starts from rest and attains a velocity
of 40 m/s in 20 s. It maintains this velocity
for 30 s and then comes to rest in 25 s.
Calculate
a) the acceleration of the car;
b) the deceleration of the car,
c) the total distance covered by the car.​

Answers

Answer 1

Answer:

a)

a = 2 [m/s^2]

b)

a = 1.6 [m/s^2]

c)

xt = 2100 [m]

Explanation:

In order to solve this problem we must use kinematics equations. But first we must identify what kind of movement is being studied.

a)

When the car moves from rest to 40 [m/s] by 20 [s], it has a uniformly accelerated movement, in this way we can calculate the acceleration by means of the following equation:

[tex]v_{f} = v_{i}+(a*t)[/tex]

where:

Vf = final velocity = 40 [m/s]

Vi = initial velocity = 0 (starting from rest)

a = acceleration [m/s^2]

t = time = 20 [s]

40 = 0 + (a*20)

a = 2 [m/s^2]

The distance can be calculates as follows:

[tex]v_{f} ^{2} = v_{i} ^{2}+(2*a*x)[/tex]

where:

x1 = distance [m]

40^2 = 0 + (2*2*x1)

x1 = 400 [m]

Now the car maintains its speed of 40 [m/s] for 30 seconds, we must calculate the distance x2 by means of the following equation, it is important to emphasize that this movement is at a constant speed.

v = x2/t2

where:

x2 = distance [m]

t2 = 30 [s]

x2 = 40*30

x2 = 1200 [m]

b)

Immediately after a change of speed occurs, such that the previous final speed becomes the initial speed, the new Final speed corresponds to zero, since the car stops completely.

[tex]v_{f} = v_{i}-a*t[/tex]

Note: the negative sign of the equation means that the car is stopping, i.e. slowing down.

0 = 40 - (a *25)

a = 40/25

a = 1.6 [m/s^2]

The distance can be calculates as follows:

[tex]v_{f} ^{2} = v_{i} ^{2} -2*a*x3\\[/tex]

0 = (40^2) - (2*1.6*x3)

x3 = 500 [m]

c)

Now we sum all the distances calculated:

xt = x1 + x2 + x3

xt = 400 + 1200 + 500

xt = 2100 [m]


Related Questions

A rocket lifts vertically off the launching pad and reaches a final velocity of 450 m/s in 15 seconds. What is its acceleration

Answers

Answer:

The answer is 30 m/s²

Explanation:

The acceleration of an object given it's velocity and time taken can be found by using the formula

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

where

v is the velocity

t is the time

From the question

v = 450 m/s

t = 15 s

We have

[tex]a = \frac{450}{15} \\ [/tex]

We have the final answer as

30 m/s²

Hope this helps you

a resistance of 60ohms allows 0.4 amps of current to flow when it is connected across a battery. what is the voltage of the battery?

Answers

Answer:

V = 24 [V]

Explanation:

To solve this problem we must use ohm's law, which tells us that the voltage is equal to the product of resistance by the current.

V = I*R

where:

V = voltage [V]

I = current [amp]

R = resistance [ohm]

Therefore:

V = 0.4*60

V = 24 [V]

Find the resultant of an easterly force of 100 N and a southeast force of 80 N acting at 65 degrees to the 100 N force

Answers

Answer:

Resultant is 152 N at 28.5 degrees south to the 100 N force

Explanation:

An apple is dropped from a 260m high building. How long will it take to hit the ground in
seconds)?

Answers

Answer:

7.28 s

Explanation:

s=-260

u=0

assume a=-9.81

t=?

s=1/2at^2 + ut

-260=1/2 (-9.81) t^2 +0t

t=7.28 s

The time taken for the apple to hit the ground from the high building is 7.28s.

Given the data in the question;

Before the apple was dropped, it was initially at rest, so

Initial velocity; [tex]u = 0 m/s[/tex]Distance or height from which it was dropped from; [tex]s = 260m[/tex]

 

To find the time it will take for the apple to hit the ground

We use the Second Equation of Motion:

[tex]s = u^2 + \frac{1}{2}at^2[/tex]

Where s is the distance or height from which it was dropped, u is its initial velocity, t is time and a is the acceleration due to gravity.

We know that earth's gravitational field or acceleration due to gravity; [tex]g = 9.8m/s^2[/tex]

Since the apple is falling, it under gravity; [tex]a = g = 9.8m/s^2[/tex]

We substitute our values into the equation and find t

[tex]260m = (0m/s)^2 + (\frac{1}{2} \ *\ 9.8m/s^2\ *\ t^2 )\\\\260m = 4.9m/s^2 \ * \ t^2\\\\t^2 = \frac{260m}{4.9m/s^2}\\\\t^2 = 53.06^2\\\\t = \sqrt{53.06s^2} \\\\t = 7.28s[/tex]

Therefore, the time taken for the apple to hit the ground from the high building is 7.28s

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Will was riding his bike when a dog ran out in front of him. He slammed on his brakes. During this quick stop, some of the mechanical energy (his motion) was changed into
A) heat energy.
B) light energy.
C) kinetic energy.
D) gravitational energy.

Answers

Answer:

A

Explanation:

big brain

During this quick stop, some of the mechanical energy (his motion) was changed into heat energy.

What is energy?

Energy is the ability to do work. There are different types of energy such as Heat energy, light energy, kinetic energy, and gravitational energy.

Heat is the energy that moves from one body to another when temperatures are different. Heat passes from the hotter to the colder body when two bodies with differing temperatures are brought together.

The joule is a unit of energy that serves as the SI unit for heat (J). The calorie (cal), which is defined as "the amount of heat necessary to raise the temperature of one gram of water from 14.5 degrees Celsius to 15.5 degrees Celsius," is another common unit of heat measurement.

Therefore, During this quick stop, some of the mechanical energy (his motion) was changed into heat energy.

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some one can help me???

An object with a mass of 2kg accelerates 10m/s2 when an unknown force is applied to it, What is the amount of the force?​

Answers

Answer: the awnser is 19k

Explanation:

Answer:

hope the answer helped you. pls mark as brainliest

Explanation:

Newton's second law states that the acceleration an object experiences due to a given force is inversely proportional to its mass, that is --

a=Fm

If the acceleration is 10m/s2 and the object's mass is 2kg , we can use Newton's second law to find that:

10m/s2=F2kg

F=20kg m/s2 , or 20N .

Which expression can be used to calculate centripetal acceleration?​

Answers

Answer:

B, 4π^2r/T^2

Explanation:

Im on the same quiz, and I'm pretty sure this is the right answer cause I found it on 4 other websites. Good luck


In a certain semiconducting material the charge carriers each have a charge of 1.6 x 10-19
C. How many are entering the semiconductor per second when the current is 2.0 nA?

Answers

Answer:

1124923453 electrons

Explanation:

The formula for charge in coulomb ,C =Current in amperes, A * Time in seconds, s

Given in question ;

Charge = 1.6 * 10⁻¹⁹ C

Current = 2.0 nA = 2*e⁻⁹ A

Calculate time in seconds as

1.6 * 10⁻¹⁹ = 2*e⁻⁹ * t

1.6 * 10⁻¹⁹ /2*e⁻⁹  = t

6.48e⁻¹⁶  s = t

So using t=6.48e⁻¹⁶  s and current =2*e⁻⁹ A , the charge will be;

C = 2*e⁻⁹  * 6.48e⁻¹⁶  =1.799e⁻¹⁰ C

But 1 coulomb = 6.25 x 10¹⁸ electrons

so 1.799e⁻¹⁰ C = ?,,,,{ 6.25 x 10¹⁸} *{1.799e⁻¹⁰} =  1124923453.06 electrons

At a race car driving event, a staff member notices that the skid marks left by the race car are 9.06 m long. The very experienced staff member knows that the deceleration of a car when skidding is -40.52 m/s2. What can the staff member estimate for the original speed of the race car if it came to a stop during the skid?

Answers

Answer:

27.1 m/s

Explanation:

Given that at a race car driving event, a staff member notices that the skid marks left by the race car are 9.06 m long. The very experienced staff member knows that the deceleration of a car when skidding is -40.52 m/s2.

Using third equation of motion,

V^2 = U^2 + 2aS

Since the car is decelerating, the final velocity V = 0

Substitute all the parameter into the equation above,

0 = U^2 - 2 * 40.52 * 9.06

U^2 = 734.22

U = [tex]\sqrt{734.22}[/tex]

U = 27.096

U = 27.1 m/s  approximately

Therefore, the staff member can estimate for the original speed of the race car to be 27.1 m/s if it came to a stop during the skid

POSSIBLE POINTS: 5
A student throws a ball upward with a force of 50.0 Newtons. The ball reaches a maximum height of 15.0 meters in 2 seconds and then returns back to
his hands. What is the direction of the acceleration at the top?
There is no acceleration at the top
O The acceleration is directed upwards away from the Earth
O The acceleration is directed downwards towards the Earth
O None of the above

Answers

Answer:

A

Explanation:

Given that a student throws a ball upward with a force of 50.0 Newtons. The ball reaches a maximum height of 15.0 meters in 2 seconds and then returns back to

his hands. 

At maximum height which is the top, the velocity is equal to zero.

According to definition of acceleration, which says; the rate of change of velocity.

Since velocity equal zero, acceleration also will be equal to zero.

Therefore, there is no acceleration at the top.

please help me this is due in 30 minutes. If you can do three that would be so great.

Answers

Answer:

1. 3000 N

Explanation:

you multiply 1000kg and 3

Answer:

2. acceleration will double

The acceleration will increase for example: 4/2=2 m/s^2 and if you double 4 it will be 8/2=4 m/s^2. Which means the acceleration also doubles.

a pulling force carried by a rope is called what

Answers

Answer:

The pulling force that acts along a stretched flexible connector, such as a rope or cable, is called tension, T. When a rope supports the weight of an object that is at rest, the tension in the rope is equal to the weight of the object: T = mg.

Explanation:

The amount of matter in a substance or object is called:
??? What the answer

Answers

Answer:

mass!!

Explanation:


Suppose y = 2x + 10. Find y if x = -2

Answers

Answer:

y = 6

Explanation:

Given parameters:

        Given equation:

                     y = 2x + 10

And supposing; x = -2

Unknown:

y = ?

Solution:

 We are going to solve this problem by substitution;

           y = 2x + 10

  since x = -2; input this into the equation to solve for y;

           y  = 2(-2) + 10 = -4 + 10  = 6

The value of y = 6

A wagon with a mass of 35 kg is pulled so that it accelerates from 0 m/s to 30 m/s in 15
seconds.
Remember to show all work!
a. What is the acceleration of the wagon?


b. What is the force required to get this acceleration?


Plz help me

Answers

Explanation:

a = v-u/t

a is the acceleration of the body

v is the final velocity

u is the initial velocity

t is the time

Given

v = 30m/s

u = 0m/s

t = 15secs

Substitute

a = 30-0/15

a = 30/15

a = 2m/s²

Hence the acceleration of the wagon is 2m/s²

b) Force = mass * acceleration

Given

Mas of the wagon = 35kg

acceleration a = 2m/s²

F = 35*2

F = 70N

Hence the force required to get this acceleration is 70N

Why do oil tankers sit lower in water

Answers

When a lower tank is damaged, the incoming sea water pushes the oil in the damaged tank up into the ballast tank. Because of the hydrostatic pressure, there is an automatic transfer out of the damaged tank. The double-hull design is aimed at the probability of zero outflow.

The shortest path between two points is:

1) displacement

2) breadth

Answers

Answer:

the shortest path between two points is displacement..

Explanation:

Hope this helps you✌️✌️

Thanks .....

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The shorts path between two points is displacement.

Calculate the TOTAL mechanical energy of pendulum is it swings from his highest point to its lowest point. Pendulum mass is 4 kg. Use your equations for gravitational potential energy and kinetic energy to determine these values based on the data given below. Total energy is the sum of gravitational potential energy and kinetic energy. In this problem, round gravity to: g = 10 m/s^2.

Answers

Answer:

its should be 2.0 and 4.5 on it

The moon euphoria is in a circular orbit around Jupiter. Which of the following describes the direction of the centripetal force acting on euphoria.
A) pointing hand into the path of its orbit
B) pointing towards the sun
C)Pointing away from Jupiter
D) pointing towards Jupiter

Answers

I think it’s A I’m not sure love but hope this helps sorry if it’s not since a Centripetal Force is a a force that acts on a body moving in a circular path and is directed toward the center around which the body is moving. You can think which one is pointing towards the center and and an object moving in a circular turn

A rocket takes off from Earth. It travels 825km in 75 seconds. What is the
speed of the rocket?
0 1 km/s
11 km/s
O 1.1 km/s
O 111 km/s

Answers

Answer:

11 km/s

Explanation:

v=s/t

v=825km/75s

v=11km/s

The cleavage furrow is formed during the telophase.

Α. True

B. False

Answers

B, False. Hope this helps!!
B false have a great one take care

For his science project, Austin wants to determine if the pH of standing rainwater changes over time. He collects rainwater and distributes it evenly in 5 jars and places them all indoors in a spot that does not receive a lot of sunlight to limit evaporation. Using a pH testing kit, he measures the pH of the water in the first jar on the 4th day, second jar on the 8th day, third jar on the 12th day, fourth jar on the 16th day and fifth jar on the 20th day. What is the independent, or manipulated, variable in Austin's experiment?

Answers

Answer:

This question lacks options, the options are:

A. the number of days the rainwater was allowed to sit

B. the number of times the rainwater was observed

C. the change in the amount of rainwater due to evaporation

D. the change in pH of the rainwater over time

The answer is A

Explanation:

In an experiment, the independent variable is the variable that is changed or manipulated by the experimenter in order to effect a measurable response.

In this experiment, Austin is trying to determine how time changes the pH of standing rainwater. He collects rainwater and distributes it evenly in 5 jars, which he measured the pH at different days using a pH testing kit. Hence, the independent or manipulated variable is THE NUMBER OF DAYS THE RAINWATER WAS ALLOWED TO SIT before measuring their pH.

difference between fundamental unit and derived unit​

Answers

Answer:

Fundamental units are the units of the fundamental physical quantities in SI system. They are not formed from other units. There are a total of seven fundamental units such as meter, kilogram, ampere, and second. Derived units are those units that are used for derived quantities.

Which two statements best determine whether an engineering design is
successful?
A. Specific project goals were met.
OB. Time and money limitations were not exceeded.
C. The project received all the necessary funding.
D. The final design was achieved with very few revisions.
D E. The completed design was popular among engineers.

Answers

Answer: A and B

Explanation:

just took the apex test

Two statements best determine whether an engineering design is

successful

A. Specific project goals were met.

B. Time and money limitations were not exceeded

What is Project in engineering design?

A "project" consists of a coordinated series of activities or tasks performed by engineers, designers, drafters and others from one or more engineering disciplines or departments.

It is important to meet the need of project what the company wants , to meet the project goals for the correct execution of the project . Setting goals can give you a clear focus , motivates employee and set target for your project  to work towards

Since , every project have a budget and a need to know if a project is worth the cost or not .

Both overestimation and underestimation of money have negative consequences and any delay in producing the end result of project can reduce the time to market and lead to reduction of profit.

correct options are

A. Specific project goals were met.

B. Time and money limitations were not exceeded.

learn more about  Project in engineering design

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the momentum of a bullet

Answers

Answer:

When a bullet is fired from a gun, total momentum before is zero since nothing is moving. After firing the bullet there is a momentum in the forward direction. ... The faster an object is moving or the more mass it has, the more momentum it has in the direction of its motion (momentum = mass velocity).

When performing a standard push-up, our hands should be placed on the ground... as close together as possible to make it the most challenging as close together as possible to make it the most challenging really wide to focus on chest development really wide to focus on chest development just outside our shoulders

Answers

Answer:

Kindly check the explanation section.

Explanation:

The statement given in the question or problem above is true or let's say it is correct. And the statement describes different kinds or types of push up.

Push up is a kind of excercise that is being done mainly to strengthen the arm and the cheat. The way one goes about it determines which part of the body one is strengthening.

The kind of push up in which one has to close up the gap between his or hands is known as the close push ups. This kind of push up strengthens the arm more than the other part of the body and the more one puts his or her hands closer the more problematic the push up excercise becomes.

Other types or kinds of push ups are the Slow Eccentric Push Ups, Wide Push Ups, Staggered Push Ups, T push ups, Fingertip Push Ups and many more.

Help PLZ ;)

If the distance between two objects increases, what happens to the force of gravity between them?
(A) Increases
(B) Decreases
(C) Stays the same

Answers

Answer:

B) Decreases

Explanation:

Gravitational force is inversely proportional to distance. As distance between 2 objects increase, gravitational force between the 2 objects decreases.

Hope this helps!

Answer:

The answer would be B

Explanation:

Is the number on a speedometer a scalar or a vector? PLS HELP !!

Answers

Scalar bs it is use to measure speed

Forensic Science-Glass

Glass fragments may adhere to __ or __ used in
a break-in.

Answers

Answer:

a

Explanation:

i had this question on edge its the first one

idk actually

How would changing the mass of a bat affect a player’s ability to swing the bat and adjust the path of the bat to hit a moving baseball or softball?

Answers

Answer:

Explanation:

The answer to that question is "both," though past players tend to have used heavier bats than do today's players. Baseball's "king of swat" Babe Ruth reportedly began his hitting career using a 54 ounce (1.5 kg) hickory bat, and is known to have used a 40oz bat in 1927 when he hit his 60 home runs.[1] Ty Cobb and Joe Di Maggio both played with 42oz bats and Rogers Hornsby used a 50oz piece of lumber. George Sisler, playing for the St. Louis Browns in the 1920's, made his bat heavier by hammering Victrola needles into the barrel of his bat.[2] In the 1950's Cincinnati Reds' Ted Kluszeski hammered tenpenny nails into his bat to make it heavier.

Other great hitters including Ted Williams, Rod Carew and Stan Musial used much lighter bats: 31-33oz.[1] Roger Maris used a 33oz bat to hit his 61 home runs in 1961. Many players have tried to make their bats lighter by drilling a hole in the barrel and filling it with cork. Detroit Tigers' Norm Cash admitted to using a corked bat in 1961 when he won the batting title with a .361 average (though he slumped to .243 the next year with the same corked bat).[2]

Kirkpatrick[3] reports that Roger Maris participated in a 1962 experiment in which he batted for distance with 5 different new bats whose weights varied from 33 to 47oz. He hit 5 long fly balls with each bat and the distances were measured and correlated to bat weight. The heavier bats, on average, resulted in further distance. However, Maris' preferred bat (which he used to break Babe Ruth's home run record) was the lightest of the set, even though it produced the shortest distance fly balls. Mark McGwire used a 35oz bat to hit his 70 home runs in 1998, and Barry Bonds used a 32oz bat to hit his 73 home runs in 2001. Most of today's major league players typically use 31-35oz bats.

Physicists have shown,[3,4] from a simple collision analysis, that the optimum bat weight is between 15 and 18oz. However, no professional batter uses a bat this light (in fact, you cannot make a wood bat this light). NCAA regulations[x] recently imposed a -3 rule (length in inches minus weigh in ounces cannot exceed 3) so that 34 inch bats must weigh 31oz. So far no such rule exists for Little League play, and -12 composite bats were introduced for the 2003 season. This brings us back to our original questions: which is better: heavier or lighter bats? So, what is the optimum bat weight, and what criteria influence this choice? Let's start by looking at the collision between ball and bat.

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