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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

Work done by lifting a mass

A person lifts a mass of 20.0 kg vertically upwards at a constant speed of 0.200 m/s through a distance of 0.800 m. What is the work done by the person? 16.0 J 156 J 3.20 J None of the other choices is correct. I know that W=M*A*D (Work equals mass times acceleration times distance) and isnt the ac

When 2 objects w/ a difference in time will become equal

A television is dropped from the top of a cliff, and 1 second later a second television is thrown downward with a velocity of 20 m/s. How far below the cliff will the second television overtake the first? Could you please show me the detailed work (with the equations) of how to achieve the answer. Our teacher gave us the an

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

Riemann tensor for the metric ds^2 = c^2dt^2 - dx^2 - a(t)^2 dy^2

1. Suppose we have a 2+1 dimensional spacetime described by the line element ds^2 = c^2dt^2 - dx^2 - a(t)^2 dy^2 where a(t) is an increasing function of time. (a) How do you interpret the spatial part of this geometry? In other words, can you describe its shape? (b) Calculate (by hand) the nonzero components of the cur

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

Thermodynamics 13.3

An insulated system takes in 6.50 kcal of heat and has 2000 J of work done on it. What is the change in internal energy if the system? I believe the answer is 29.2 kJ. I need to see each step and formula to solve this question. Please assume I know nothing because this would be the correct assumption. :)

Thermal Expansion 11.22

(a) How many joules are required to raise 1.0 kg of water from room temperature of 22^oC to its boiling point? (b) If this work were used to lift a 50-kg boy instead, how high could he be lifted? I need to see each step and formula to solve this question.

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 5.0g bullet if fired horizontally into a 2.0kg wooden block resting on a horizontal surface. The coefficient of kinetic friction between block and surface is 0.20. The bullet remains imbedded in the block, which slides 0.105m along the surface. What was the initial speed of the bullet? (My problem with this is that there is no

Work, Energy, Friction

A car is travelling on a level road with speed v1 at the instant when the brakes are applied. Assume that the wheels are locked and the car is skidding, so the friction force between the tires and the road is kinetic friction with coefficient mu_k. a) Use the work-energy relation to calculate the minimum stopping distance of