Log in
Physics
1
answer
0
watching
92
views
23 Nov 2019

I have found this website to be very helpful understanding how to better work through my problems. I'm taking a general physics 202 class and need some help figuring out questions in my lab manual. Is there anywhere on this site that has step by step answers to problems in lab manuals?

Watch
1
answer
0
watching
92
views

For unlimited access to Homework Help, a Homework+ subscription is required.

Unlock all answers

Get 1 free homework help answer.
Already have an account? Log in
Share

Related textbook solutions

Physics: Principles with Applications
7th Edition, 2013
Giancoli
ISBN: 9780321625922

Related questions

I'm working on a lab for my physics lab, and I'm supposed to analyze hypothetical results of a weighted car being pulled across a table top with a constant hanging mass, while mass is being added to the car, making the total mass a change. I have to make a graph on Microsoft Excel with the data (acceleration of car vs. 1/total mass) and decide what type of proportion it is, the slope of the graph, the physical meaning of the slope units, and the relationship between the force acting on the car and the slope of the graph. Going through this process, I have found the graph to be inversely proportional, have a negative slope of 0.2467, but cannot for the life of my figure out the physical meaning for the slope units or the relationship between the force and the slope. Is there any way you can help??? The units for acceleration is meters per second squared and the 1/total mass is in kilograms. The force of the hanging mass acting on the car is a constant of 1.96 Newtons. What is going on???

In order to solve the problem you must refer to the first partwhich i already solved and I am 200% sure of the answers, however Iam stuck on the second part and I need help asap. Please do not getscared when you look at this problem and thank you soo much inadvance.

A wheel 75 meters in diameter is mounted vertically on an infinitefrictionless plane at the origin. The infinite frictionless planehas a grid of Cartesian coordinates on it. The moment of inertia ofthe wheel is mr^2. The mass of the wheel is 2000kg. There is anengine connected to the wheel that can produce a torque of 2.34x10^6 Nm. There is a 50 kg object attached to the circumference ofthe wheel that is attached to the wheel with a remote releasemechanism. The wheel is placed on the origin so that the plane ofthe wheel contains the point x=50 meters and y=86.8 m. The wheel ispositioned so that the object is just above the plane at the 6o'clock position. The engine is engaged and begins to apply thetorque to the wheel at 12:00 noon on March 1, 2011. The wheelbegins to rotate in the counterclockwise direction. The torque isapplied for 4 x 10^4 revolutions. At that point the object isreleased from the wheel and a 75 Newton motor accelerates theobject in the direction it is released. The motor is fired for 2.34x 10^4 seconds. (the following questions i have already answered)What is the angular velocity and rotational KE of the object justbefore it is released? (answer for that is 6.39 x 10^2 rad/sec and5.89 x 10^11 J). What angle does the path of the object make withthe x axis? (answer is 60.05 degrees). Where is the object on theinfinite frictionless plane when the motor stops (what are itscoordinates....answer is x=4.85x10^8m y=8.40x10^8m). What is thevelocity and linear KE of the object when the motor stops?(5.91x10^4 m/sec and KE= 8.73 x 10^10J). How much work was done onthe object up until the time the motor stopped? (8.73 x 10^10J).(Hint: the mass of the wheel is 2050 kg while the torque is appliedand the object is attached).

YEA I know what you are thinking at this moment. Difficult right?Please give it a chance and have faith in yourself. Here is thepart I had difficulty with:

After the engine stops firing the object is turned around so thatthe engine can be used to stop the object. The motor is fired atits rated thrust to stop the object. Unfortunately it malfunctionsand shuts down after an hour and the object coasts from then on. Atthe end of an hour of coasting it encounters a ramp that is 2000meters high and slopes up at an angle of 20 degrees. The objectclimbs the ramp and flies off the ramp into the air when it reachesthe end of the ramp. It strikes the plane and digs a crater 5meters deep in the plane and comes to a stop. How far from the endof the ramp does it land? Where does it land on the plane (as incoordinates)? What is the resultant velocity of the object and whatis the acute angle of the resultant velocity with the plane when itstrikes the plane? What is the KE of the object when it hits theplane? What date and time is it when the object lands on the plane?How much work was done on the object to stop it? How long did ittake to stop? What was the deceleration of the object in m/sec^2?What was the force on the object in Newtons to stop it?

If you are from MIT I have faith that you can do this. I am only ajunior in high school taking first year physics that is not evenAP. My teacher is from MIT and said he did this kind of stuff whenhe was there. Please please please help me! I'm desperate.

A boy in a wheelchair (total mass 50.5 kg) has a speed of 1.40 m/s at the crest of a slope 2.40 m high and 12.4 m long. At the bottom of the slope, his speed is 6.50 m/s. Assume air resistance and rolling resistance can be modeled as a constant friction force of 41.0 N. Find the work he did in pushing forward on his wheels during the downhill ride.

 

 
 
 

2 Answers

Relevance
  • electron1
    Lv 7
    4 years ago

    There are two forces that cause the wheelchair to accelerate. These two forces are the component of the wheelchair’s weight that is parallel to the hill and the force the boy exerts. The net force on the wheelchair is equal to the sum of these two forces minus the friction force. Let’s use the following equation to determine the acceleration.

     

    vf2 = vi^2 + 2 * a * d

    6.5^2 = 1.4^2 + 2 * a * 12.4

    24.8 * a = 40.29

    a = 40.29 ÷ 24.8

    This is approximately 1.62 m/s^2.

     

    Net force = 50.5 * 40.29 ÷ 24.8 = 2034.645 ÷ 24.8

    This is approximately 82 N.

     

    Force parallel = 50.5 * 9.8 * 2.40 ÷ 12.4 = 1187.76 ÷ 12.4

     

    This is approximately 95.8 N. This force and the force that the boy exerts are the forces that cause the wheelchair to accelerate.

     

    Net force = F + (1187.76 ÷ 12.4) – 41

    Set the two net forces equal to each other.

     

    F + (1187.76 ÷ 12.4) – 41 = 2034.645 ÷ 24.8

    F = 41 + (2034.645 ÷ 24.8) – (1187.76 ÷ 12.4)

    F is approximately 27.3 N

     

    Work = [41 + (2034.645 ÷ 24.8) – (1187.76 ÷ 12.4)] * 12.4 = 337.9625 J

     
  • JupiterSky
    Lv 6
    4 years ago

    His change in kinetic energy is due to gravitational- and his own work,

    while the friction does negative work.

     

    ∆K = ∆U +∆W + ∆Wf

    ½m(Vf²−Vi²) = mgh + ∆W + Ff*d

    ∆W = ½m(Vf²−Vi²) − mgh − Ff*d

    ∆W = ½*50.5(6.5²−1.4²) − (50.5*9.8*2.4) − (−41*12.4)

    ∆W = 508 J

     
Still have questions? Get your answers by asking now.
 
 
Next Question
---
asked in Science & MathematicsPhysics · 8 years ago

What is the spring constant? please help me!!!!?

A block of mass 487 g is pushed against the

spring (located on the left-hand side of the

track) and compresses the spring a distance

4.7 cm from its equilibrium position (as shown

in the figure below). The block starts from

rest, is accelerated by the compressed spring,

and slides across a frictionless horizontal track

(as shown in the figure below). It leaves the

track horizontally, flies through the air, and

subsequently strikes the ground.

acceleration = 9.81

 

A) What is the spring constant?

B)What is the speed v of the block when it leaves

the track?

C) What is the total speed of the block when it

hits the ground?

...Show more
Update:

Height Above ground = 1.9 m

Lands = 4.59m away

 
What is the spring constant? please help me!!!!?

3 Answers

Relevance
  • Jánošík
    Lv 7
    8 years ago
    Favorite Answer

    I'm sure there is some crucial information in "the figure below" !!!

     

    Edit:

    OK... now we got something to work with ... ;-)

     

    Time needed to fall a vertical distance of 1.9 m is:

    t = √( 2h / g )

    t = √[ 2×(1.9 m) / (9.81 m/s²) ]

    t = 0.6224 s

     

    In that time, the block must travel a horizontal distance of 4.59 m, so the horizontal velocity is:

    r = v×t

    (4.59 m) = v×(0.6224 s)

    v = 7.37 m/s < - - - - - - - - - - - - - - - - - answer B

     

    That is also the speed of the block as it leaves the spring.

    Its kinetic energy at that time is:

    KE = m×v²/2

    KE = (0.487 kg)×(7.3749 m/s)²/2

    KE = 13.244 J

     

    That is also the elastic potential energy stored in the spring at maximum compression. So the spring constant is:

    KE = PEe = k×d²/2

    (13.244 J) = k×(0.047 m)²/2

    k = 12 N/m < - - - - - - - - - - - - - - - - - - answer A

     

    The gravitational potential energy of the block on the table is:

    PEg = m×g×h

    PEg = (0.487 kg)×(9.81 m/s²)×(1.9)

    PEg = 9.077 J

     

    The total energy of the block on the table is:

    TE = PEg + PEe

    TE = (9.077 J) + (13.244 J)

    TE = 22.32 J

     

    When hitting the ground, all that energy is converted to kinetic energy, so

    TE = KE = m×v²/2

    (22.32 J) = (0.487 kg)×v²/2

    v = 9.57 m/s < - - - - - - - - - - - - - - - - - - answer C

    ...Show more
     
  • Technobuff
    Lv 7
    8 years ago

    There must be a height above ground and a distance from the end of the track on the "as shown in the figure below".??

     
  • STALKER
    Lv 4
    8 years ago

    use f=kl

     

    where k is the spring constant and l is extension from the natural length.

     

    k=f/l

     

    since you have mass in grams. use w=mg

     

    w=0.487 x 9.8 = 4.77N

     

    Now use the equation,

     

    k=4.77/4.7

     

    k=1.012

     

    Note: my answer could be wrong since I do not know the springs original length from the diagram shown. But, the method of working out spring constant is same.

    ...Show more
     
Still have questions? Get your answers by asking now.
Next Question
ひいらぎ
Lv 5
asked in Science & MathematicsPhysics · 1 decade ago

Physics Momentum, Rolling?

Pat builds a track for his model car out of wood. The track is 10.00 cm wide and 3.00 m long, and is solid. The runway is cut such that it forms a parabola by the equation y=(x - 3)^2/9. Locate the horizontal position of the center of gravity of this track.

 

A washing machine load in the "spin" cycle, (much like a centrifuge used to separate fluids), can be modeled as a cylinder which has zero density toward the center, and starting from some inner radius where the clothes (or fluids) begin, increases in density as you move radially outward. The washing machine has density of clothes (in SI units) of p=14r+5, a height of 0.51 m, and only has clothes present from inner radius 0.2m out to 0.7m from the center.

-What is the moment of Inertia of the wash load?

-What is the power of motor that drives the clothes from rest up to 4 rev/sec, in 14 seconds if the basin has moment of Inertia of 4 kg*.m2

...Show more
 
Physics Momentum, Rolling?

1 Answer

Relevance
  •  
    Anonymous
    1 decade ago
    Favorite Answer
     

    I can't visualize the first problem.

     

    The second: Moment of inertia is I = m r^2. In a shell of thickness dr there is a mass of p * 2 * pi * r * h * dr. The moment of inertia of the shell is 2 pi h p r^3 dr. Now integrate this from r = 0.2m to r = 0.7m.

     

    Kinetic energy is 1/2 m v^2. In rotations the moment of inertia is like the mass and the angular velocity is like the velocity, so rotational energy is 1/2 I omega^2. Omega is in rad/s. The total inertia of the system is the sum of the inertia of the clothes and the basin. Divide the energy by the time needed to get the power.

    ...Show more
     
Still have questions? Get your answers by asking now.
Next Question
AZ
asked in Science & MathematicsPhysics · 1 decade ago

Physics:You and your friends push a 75-kg...Help!?

You and your friends push a 75-kg greased pig up an aluminum slide at the county fair, starting from the low end of the slide. The coefficient of kinetic friction between the pig and the slide is 0.070.

 

(a) All of you pushing together (parallel to the incline) manage to accelerate the pig from rest at the constant rate of 4.9 m/s2 over a distance of 1.8 m, at which point you release the pig. The pig continues up the slide, reaching a maximum vertical height above its release point of 50 cm. What is the angle of inclination of the slide? __degree

 

(b) At the maximum height the pig turns around and begins to slip down the slide, how fast is it moving when it arrives at the low end of the slide? __m/s

...Show more
 
Physics:You and your friends push a 75-kg...Help!?

1 Answer

Relevance
  •  
    Anonymous
    1 decade ago
    Favorite Answer
     

    ♣the distance the pig was pushed up is

    s=0.5*a*t^2, where s=1.8m, a=4.9m/s^2, t is time of push-up;

    speed of the pig gained after s=1.8m is v=a*t; thus v^2=2as;

    ♠ kinetic energy of the pig at the moment it’s released after push-up is

    E=0.5*m*v^2, which is enough for the pig to move by itself L distance more along the ramp, where L=h/sin(b), h=50cm=0.5m, b is angle in question;

    ♦pig’s potential energy at vertex (when stopped) is E1=mgh;

    the energy E2=E-E1 is gone on friction, that is E2=f*L is work of friction, where

    f=μ*w1, w1=mg*cos(b) is component of pig’s weight normal to the aluminum ramp; or;

    f= μ*mg*cos(b);

    ♦Thus E2=E-E1; or; f*L = 0.5*m*v^2 –mgh; or;

    (μ*mg*cos(b)) * (h/sin(b)) =0.5*m* 2as –mgh; or;

    μ*gh*cos(b)/sin(b) =as –gh, hence cot(b) =(as –gh)/(μ*gh), hence

    (a); b=atan(μ*gh/(as-gh))= atan(0.07*9.8*0.5/(4.9*1.8 -9.8*0.5)) =5°;

     

    ♥ pig’s potential energy above the low end of the ramp is

    W= mg*(s*sin(b) +h); pig’s ramp position is p=s +L = s + h/sin(b);

    Pig’s final kinetic energy is W1=W-W2, where W2=f*p is work of friction;

    and W1=0.5*m*v^2; thus

    0.5*m*v^2 = mg*(s*sin(b) +h) – μ*mg*cos(b)*(s + h/sin(b));

    v^2 =2g*(s*sin(b) +h)*(1 –μ*cot(b)) =2.575;

    (b); v =1.605 m/s;

    ...Show more
     
Still have questions? Get your answers by asking now.
 
+100
Join Yahoo Answers and get 100 points today.

Trending Questions

  • what is centripetal vs centrifugal in terms of circular motion?
    8 answers
  • The Universe cant magic into existence, it has to have a cause. If it has a cause, it can only be eternal?
    10 answers

  •  

  •  

Weekly leaderboard

Home
Homework Help 3,900,000
Physics 110,000
Start filling in the gaps now
Log in