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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 = _______.

Particles and Waves

1.) In a television picture tube the electrons are accelerated from rest through a potential difference V. Just before an electron strikes the screen, its de Broglie wavelength is 0.8*10^-11 m. What is the potential difference? 2.) A photon has the same momentum as an electron moving with a speed of 1.6 *10^5 m/s. What is t

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

Rolling Ball

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

average thermal power

A 10.0 kg rock slides on a rough horizontal surface at 6.50m/s and eventually stops due to friction. The coefficient of kinetic friction between the rock and the surface is 0.300. What average thermal power is produced as the rock stops?

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

Energy, Momentum and Projectile Motion

please include all diagrams and calculations and assumptions The object of a pinball game is to project the "particle" (the red ball) so that it enters the hole at E. When the spring is compressed and then released the particle is projected along the track which is smooth except for a rough patch between a and b where the c

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.

Amount of work to accelerate

Suppose I put in 10keV (1eV = 1.6 x10-19J; 1keV = 103eV) of work to accelerate an electron (rest mass = 9.1x10-31 kg). With this amount of work, up to what speed (in terms of c) can the electron be accelerated if it starts from rest?

Energy Stored in a Spring

The force exerted by an unusual spring when it is compressed a distance x from equilibrium is given by F = -kx-cx^3, where k=220 N/m and c=3.6 N/m^3. Find the energy stored in this spring when it has been compressed by 15 cm.

Magnitude of a Force

A 5.0 kg object moving on a horizontal surface has an initial velocity, vi=(5.0i+10.0j) when a force F acts on the object for 3 seconds after which velocity is vf=(10i+30j) m/s. Determine the work done by the force F on the object. What is the magnitude of the force F?

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


A disk with rotational inertia of 5.0 kg*m^2 and radius of 0.25m rotates on a fixed perpendicular axis through its center. A force of 2N is applied tangentially to the rim. As the disk turns through half a revolution what is the work done by the force?

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 Figure ??, 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 bridge, where a

Gravitational force as object moves up inclined plane

What is the amount of work done by the gravitational force as an object with a mass of 2.00 kg moves up an inclined plane that rises at an angle of elevation of 30 degrees? The question refers to the instant when the object has moved 0.600 m along the surface of the inclined plane in the upward direction. Neglect friction and

Work done by applied force

A 100 kg object is pulled vertically upwards by a constant force of 4000 N for a distance of 20.0 m. What is the work done by the applied force on the object? 60,400 kg m/s 80,000 kg m/s 80,000 kg m^2/s^2 60,400 kg m^2/s^2