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Simple Machines: Force required to push a box up a ramp.

1. A 400-lb piano on frictionless casters is to be pushed up a 20 ft ramp to a loading platform 3 ft above the ground. How much force is needed? 2. A block weighing 250 lbs is to be raised into a wagon 30 in high by a boy who can only exert a force of 50 lbs. (a) what is the shortest board he must use as an inclined plane wh

Photoelectric Effect: Energy of Photoelectrons Emitted

Light from a laser hits the surface of cesium. With a minimum photon energy of 2.14eV being required to remove photons. When the surface of cesium is illuminated with this light photoelectrons are emitted with a max kinetic energy of 0.76eV. Assuming that the Planck constant is 4.14x10^-15 eV Hz-1. What would be the energy of

Work & Power

Work & Power - Involves you walking up a flight of stairs and recording your time via a stopwatch or chronograph.You will be asked to make measurements and calculations for the total time to walk the flight of stairs (at least 7 steps) and the vertical height of the stairs from the bottom to the top. o Estimate your mass in kg

Atwood's Machine

In a simulation, m1 is 1.0 kg and m2 is 1.1 kg. Mass m2 rests on the floor that exerts a normal force, FN, on m2. There is no motion (i.e.. the system is in equilibrium). What is the normal force, FN, and what is the tension, T, in the rope? T (at t = 2.54 s) = ______. At equilibrium: FN + T - m2 ? g = 0. Then FN = _______.

Energy and work

Please see attachment. 12. A rock is thrown straight up from the surface of the Earth. Which one of the following statements describes the energy transformation of the rock as it rises? Neglect air resistance. 13. A helicopter is cruising at a speed of 25.0 m/s at an altitude of 185 m. What is the total mechanical energy of

uniform ball and silver dollar rolling down a curved track

In a lab experiment you let a uniform ball roll down a curved track. The ball starts from rest and rolls without slipping. While on the track, the ball descends a vertical distance h. The lower end of the track is horizontal and extends over the edge of the lab table; the ball leaves the track traveling horizontally. While free

Swing - Potential energy, speed etc.

A 23.0 kg child plays on a swing having support ropes that are 1.90 m long. A friend pulls her back until the ropes are 39.0 (degrees) from the vertical and releases her from rest. Part a: What is the potential energy for the child just as she is released, compared with the potential energy at the bottom of the swing? V=

Work done by earth on moon and by sun on earth.

Assume that the earth and the moon have circular orbits (which is almost true) and that the periods of their orbits are 365 days and 28.0 days, respectively How much work does the earth do on the moon in one day? W(earth)= ? J How much work does the sun do on the earth in one month? W(sun)= ?J

Work done on a cutting tool.

A cutting tool under microprocessor control has several forces acting on it. One force is F = -alpha xy^{2} hat{ j }, a force in the negative y-direction whose magnitude depends on the position of the tool. The constant is alpha = 2.25 N/m^3. Consider the displacement of the tool from the origin to the point x = 2.10 m, y = 2.

angular velocity of the particle and work done

A particle of mass m is moving on a frictionless horizontal table and is attached to a massless string, whose other end passes through a hole in the table, where I'm holding it. Initially, the particle is moving in a circle of radius r0 with angular velocity w0, but I now pull the string down through the whole until at length r

change in electric potential energy

1. A uniform electric field with a magnitude of 6050 N/C points in the positive x direction. Find the change in electric potential energy with a +12.5-µC charge is moved 5.50 cm in (a) the positive x direction (b) the negative x direction, and (c) in the positive y direction. 2. Points A and B have electric potentials of

Calculate the tension of the string in Newtons.

The goal is to give a guitar maker a list of the separation between successive frets on the neck of the guitar. In the figure attached, the frets are the thin metal bars transverse to the neck of the instrument. When a string is pressed against a fret with a finger, its effective length is the distance from the fret to the bridg

Probability of energy flowing into a subsystem

Suppose we have two blocks composed of 6 harmonic oscillators each and have 3 quanta in each initially. After bringing them together, what is the probability of having all the energy move to one of the blocks?

Modern Physics Multiple Choice Questions

1. Use the work-energy theorem to find the force required to accelerate an electron (m = 9.11 x 10-31 kg) from rest to a speed of 1.50 x 107 m/s in a distance of 0.0125 m. a. 8.20 x 10-15 N b. 5.47 x 10-22 N c. 8.20 x 10-17 N d. 1.64 x 10-14 N e. 3.56 x 10-19 N 2. Use the work-energy theorem to find the force requir

A pitcher throws a baseball with mass=.145kg straight up with initial v=25 m/s

A pitcher throws a baseball with mass=.145kg straight up with initial v=25 m/s a) How much work has gravity done on the ball when it reaches h=20m above pitcher's hand? b) Using work-energy theorem, calculate speed of baseball at h=20m above pitcher's hand c) Does the answer to part b depend on weather the ball is moving up

Potential energy

A shot-putter puts a shot (weight=0.71 N) that leaves his hand at a distance of 1.52 m above the ground. a.) What is the work done by the gravitational force when the shot has risen to a height of 2.13 m above the ground. d.) What is the change in the gravitational potential energy of the shot.

Barrel on inclined plane

A 40 kilogram barrel is rolled up a 10 meter ramp to a hieght of 5 meters. A) How much does the barrel weight? b) How much work was done? c) If the person exerted an effort force of 250 newtons to roll the barrel along the ramp, what is the efficiency of the ramp?

kinetic energy and distance penetrated by the pile

A pile is driven into the ground by a hammer of mass (M) 500Kg, dropped from a height of 4 meters. The mass (m) of the pile is 40Kg and the average resistance of the ground to penetration (Fr) is 45 kN. 1) Calculate the Velocity and the kinetic energy of the hammer prior to the impact with the pile. 2) Calculate the velo

In moving out of a dormitory at the end of the semester

In moving out of a dormitory at the end of the semester, a student does 1.6 x 10^4 J of work. In the process, his internal energy decreases by 4.2 x 10^4 J. Determine each of the following quantities (including the algebraic sign): (a)W, (b) delta U, and (c)Q.

Varying coefficient of friction

A box is sliding with a speed of 4.50 m/s on a horizontal surface, when at point P, it encounters a rough section. On the rough section, the coefficient of friction is not constant, but starts at 0.100 at P and increases linearly with distance past P, reaching a value of 0.600 at 12.5 m past point P. a) use the work-energy

Rotational mechanics, hydrostatics and hydrodynamics.

1 The arm in Figure P8.7 weighs 36.0 N. The force of gravity acting on the arm acts through point A. Determine the magnitudes of the tension force t in the deltoid muscle and the force s of the shoulder on the humerus (upper-arm bone) to hold the arm in the position shown. 2. One end of a uniform 6.0 m long rod of weigh

Friction Problems

See attached file for full problem description. --- 1. a) A block with a mass m is pulled along a horizontal surface for a distance +x by a constant force F at an angle theta with respect to the horizontal. The coefficient of kinetic friction between block and table is µ. Is the force exerted by friction equal to µmg?

Physics/ answers to questions

1. Which one of the following statements best explains why it is possible to define an electrostatic potential in a region of space that contains an electrostatic field? a. Work must be done to bring two positive charges closer together b. Like charges repel one another and unlike charges attract one another c. A positive c

Work-Energy Concepts

A little red wagon with a mass of 4.60 kg moves in a straight line on a frictionless horizontal surface. It has an initial speed of 10.0m/s and then is pulled 4.0 m by a force with a magnitude of 18.0 N in the direction of the initial velocity. a) Use the work-energy relation to calculate the wagon's final speed. b) Calculate

Forces in parallel

2 forces parallel to the X axis do 14.7 Joules of work on a small tray while moving it 20.7 meters in the X direction across a gym floor. One of the forces has a value of +3.89 Newton's in the X direction. What is the other force?

Heat and Thermodynamics: Work done in a cycle

Please explain problem in word or pdf format closed path with 4 processes 1st process Isochoric V= 2m^3 P-initial = 3x10^4 Pa P-final = 8x10^4 Pa 2nd process Isobaric V-initial = 2m^3 V-final= 5m^3 P = 8x10^4 3rd process Isochoric V= 5m^3 Pi =8x10^4 Pa Pf =3x10^4 Pa 4th process Isobaric Vi = 5m^3

Using the Work-Energy Theorem

Pushing a Cat. Your cat "Ms." (mass 7.00 kg) is trying to make it to the top of a frictionless ramp 2.00 m long and inclined upward at 30.0 degree above the horizontal. Since the poor cat can't get any traction on the ramp, you push her up the entire length of the ramp by exerting a constant 100-N force parallel to the ramp.