Questions
Three forces act on an object. the first force is 37.5 lbs at 130.0 degrees, the...

Three forces act on an object. the first force is 37.5 lbs at 130.0 degrees, the second force is 28.0 lbs at 30.0 degrees east of south, and the third force is 11.0 lbs due south. What is the net force (magnitude and direction) exerted on this body?

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You want to calculate the location of the center of gravity of a person lying on...

  1. You want to calculate the location of the center of gravity of a person lying on his back. His legs have a mass of 20 kg and the center of gravity of his legs is 0.35 m from the bottom of his feet. His trunk and arms have a mass of 50 kg and the center of gravity of these body parts combined is 1.2 m from the bottom of his feet. His head has mass of 5 kg and the center of gravity of the head is 1.6m from the bottom of his feet.

    1. What is the weight of each body segment and the total body weight?

    2. What is the torque produced by each body segment about an axis through the bottom of his feet?

    3. What is the sum of these torques?

    4. How far from the bottom of the feet is his center of gravity?

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A blue car with mass mc = 537 kg is moving east with a speed of...

A blue car with mass mc = 537 kg is moving east with a speed of vc = 20 m/s and collides with a purple truck with mass mt = 1380 kg that is moving south with an unknown speed. The two collide and lock together after the collision moving at an angle of θ = 56° South of East1)What is the magnitude of the initial momentum of the car?

2)

What is the magnitude of the initial momentum of the truck?

3)

What is the speed of the truck before the collision?

4)

What is the magnitude of the momentum of the car-truck combination immediately after the collision?

5)

What is the speed of the car-truck combination immediately after the collision?

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Figure (a) shows three plastic sheets that are large, parallel, and uniformly charged. Figure (b) gives...

Figure (a) shows three plastic sheets that are large, parallel, and uniformly charged. Figure (b) gives the component of the net electric field along an x axis through the sheets. The scale of the vertical axis is set by Es = 9

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A laser beam with vacuum wavelength 573 nm is incident from air onto a block of...

A laser beam with vacuum wavelength 573 nm is incident from air onto a block of Lucite as shown in the figure below. The line of sight of the photograph is perpendicular to the plane in which the light moves. Take ?1 to be 61

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Mass on a spring 1-By doubling the mass of the objet attached to the spring the...

Mass on a spring

1-By doubling the mass of the objet attached to the spring the period of the oscillations will change by a factor of

-

4

-

0.5

-

1.4

-

2

2-According to Hook's Law, the force of a spring is proportional to

-the change in the length of the spring

-the length of the spring

-the mass of the spring

-the change in the mass of the spring

3-The units for the spring constant are

-N/m

-

N

-N/kg

-m/s2

4- A 0.26kg object is placed at the end of a vertical spring. The unstretched (natural) length of the spring is 0.24m. After adding the mass the final length is 0.38m. What is the spring constant (in N/m)?

5- A 0.39kg object is placed at the end of a vertical spring with a spring constant k=23.43N/m . Assuming the spring is massless, what would be the period of oscillations (in s) ?

6- In the previous problem, what is the theoretical value for the period of oscillations, if the hanging mass is 0.2kg and the spring is massless?

-

2s

-

1s

-

0.6s

-

1.4s

7- In the previous problem what is the theoretical value for the period of the oscillations, if the mass is 0.2 kg and the mass of the spring is 0.15 kg?

-

2.1 s

-1.2 s-

- 0.67 s

- 1.5 s

8- The period of oscillations for a mass spring system would ___ if the experiment was done on the surface of the moon. NOTE: The acceleration due to gravity on the surface of the moon is 1/6th of the acceleration due to gravity on Earth.

-

quadruple

-

double

- increase by a factor of 6

-

stay the same

9- The potential energy of a mass-spring system when the spring is fully compressed and the mass is at rest is 200 J. After releasing the mass, assuming there is no dissipative force, the system will oscillate. At a point during the oscillation the potential energy of the system is 50 J. What is the kinetic energy of the mass at that point, assuming the spring is massless?

-

50 J

-

250 J

-

150 J

-

200 J

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The proper mean lifetime of a muon is 2.2ms. Muons in a beam are traveling through...

The proper mean lifetime of a muon is 2.2ms. Muons in a beam are traveling through a laboratory at 0.95c.

1. What is their mean lifetime as measured the laboratory?

2. How far do they travel, on average, before they decay?

Please show expressions, work, and a proper explination!!!

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A 0.26 kg mass is attached to a light spring with a force constant of 36.9...

A 0.26 kg mass is attached to a light spring with a force constant of 36.9 N/m and set into oscillation on a horizontal frictionless surface. If the spring is stretched 5.0 cm and released from rest, determine the following.

(a) maximum speed of the oscillating mass
m/s

(b) speed of the oscillating mass when the spring is compressed 1.5 cm
m/s

(c) speed of the oscillating mass as it passes the point 1.5 cm from the equilibrium position
m/s

(d) value of x at which the speed of the oscillating mass is equal to one-half the maximum value
m

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Problem 24.96 Infinite positively charged sheet 1 has uniform surface charge density σ1 = +2.0 nC/m2...

Problem 24.96 Infinite positively charged sheet 1 has uniform surface charge density σ1 = +2.0 nC/m2 and is located in the yz plane of a Cartesian coordinate system. Infinite negatively charged sheet 2 is parallel to sheet 1 and has uniform surface charge density σ2 = -5.0 nC/m2 . Sheet 2 is 4 m to the right of sheet 1 along the +x axis.

Part A

Determine the magnitude and direction of the electric field in region I, to the left of sheet 1.

Express your answer with the appropriate units. Enter positive value if the field is in positive x direction and negative value if the field is in negative x direction.

EI

EI

=

339StartFraction Upper N Over Upper C EndFractionNC

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Incorrect; Try Again; 4 attempts remaining

Part B

Determine the magnitude and direction of the electric field in region II, between the two sheets.

Express your answer with the appropriate units. Enter positive value if the field is in positive x direction and negative value if the field is in negative x direction.

EII

EII

=

nothingnothing

SubmitRequest Answer

Part C

Determine the magnitude and direction of the electric field in region III, to the right of sheet 2.

Express your answer with the appropriate units. Enter positive value if the field is in positive x direction and negative value if the field is in negative x direction.

EIII

EIII

=

nothingnothing

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(a)One end of a string is attached to a wall and the other end is attached...

(a)One end of a string is attached to a wall and the other end is attached to a mass sitting on a ramp tilted at an angle of 35 degrees. It takes a pulse 10 ms to travel the length of the 1 m string. The string has a mass 1.5 g. What is the mass that is attached to the string?

 

(b) The string is replaced by two strings that are knotted together, L1 has a length 60 cm and L2 has a length of 40 cm. They have a linear mass density of of mu1 = 1.4 x 10-4 kg/m and mu2 = 2.8 x 10-4 kg/m. Like before, they are attached to the mass you found in part a. A pulse is sent from each end of the string. Which pulse meets the knot first?

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Suppose I pour 13.5 mL of creamer into 159 mL of hot coffee. The creamer is...

Suppose I pour 13.5 mL of creamer into 159 mL of hot coffee. The creamer is at 43.4 deg F, and the coffee is at 188 deg F. What is the final temperature when the system reaches equilibrium, in deg F? Assume coffee and creamer have the same density and thermal properties of water.

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Three people talk simultaneously. If the intensity level is 92 dB when either one speaks alone,...

Three people talk simultaneously. If the intensity level is 92 dB when either one speaks alone, what is the intensity level when both speak at once?

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Two converging lenses are separated by 29.00 cm. The focal length of each lens is 17.00...

Two converging lenses are separated by 29.00 cm. The focal length of each lens is 17.00 cm. An object is placed 32.00 cm to the left of the lens that is on the left. Determine the final image distance relative to the lens on the right.

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1. An object of mass 1.5 kg, attached to a string, swings back and forth like...


1. An object of mass 1.5 kg, attached to a string, swings back and forth like a pendulum in the vertical xy-plane. At one point in the motion, when the object is on the right side of the swing, its velocity is measured to be m/s.
a) In what direction is the object moving at this point in its motion? Draw a physical picture and the path of the object, with a velocity arrow at this point in the motion.
b) Since the string is in contact with the object, they exert forces on each other. Make a reasoned argument how the object exerts a force on the string, and then use Newton’s third law to draw an arrow to represent the force that the string exerts on the object at this point in the motion.
c) Identify all other forces that are acting on the object and draw arrows to represent these forces. Explain how you know the directions of these forces.
d) Use a pictorial arrow addition to determine the net force acting on the object at this point in its motion.
e) Based on a reasoned argument of the object’s speed and direction of motion a short time later, estimate the object’s velocity at a small time later in its motion. Use a pictorial diagram to draw arrows to determine the change in the object’s momentum between these two points.
f) Based on your estimates, calculate the magnitude and direction of the change in momentum.
g) Based on your diagrams in (d) and (e), decide if Newton’s 2nd law is upheld. If not, explain what you should change in your diagrams to get agreement, and why.

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5 kg of saturated liquid water at 10 bars is contained in a piston-cylinder assembly and...

5 kg of saturated liquid water at 10 bars is contained in a piston-cylinder assembly and undergoes two processes. process 1-2: heated at constant pressure until it is saturated vapor. process 2-3: cooled as it is compressed at constant volume until it reaches 110 degrees celsius. determine the overall work and heat transfer for these processes. Hint: Must used linear interpolation from values in the correct Water tables.

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