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# Work

### Ball slided down incline and encounters rough surface

1.) A 1-kg ball starting at h = 7.2 meters slides down a smooth surface where it encounters a rough surface and is brought to rest at B, a distance 26.6 meters away. To the nearest joule what is the work done by friction? 2.) To two decimal places, what is the coefficient of friction? See attached file for full problem des

### Work performed by a skier: Example problem

A skier of mass 69.3 kg is pulled up a slope by a motor-driven cable. (a) How much work is required to pull him a distance of 59.0 m up a 30.4° slope (assumed frictionless) at a constant speed of 1.97 m/s? (b) A motor of what power is required to perform this task?

### Physics Review

Mark the following statements true or false. If you mark it false, tell why it is false and how it could be changed to make it true. 1. If a force F acts on a particle of mass m which is moving at a speed v, we define the work done to be the change in the quantity 1/2mv^2. 2. Work is necessarily a positive quantity. 3.

### Independent Wing Span Size Analysis

Question78: All birds, independent of their size, must maintain a power output of 10 to 25 watts per kilogram of body mass in order to fly by flapping their wings. (a) The Andean giant hummingbird (Pantagona Gigas) has a mass of 70g and flaps its wings ten times per second while hovering. Estimate the amount of work done

### Energy is conventionally measured in Calories

Energy is conventionally measured in Calories as well as in joules. One Calorie in nutrition is one kilocalorie, defined as 1 kcal = 4186 J. Metabolizing one gram of fat can release 9.00 kcal. A student decides to try to lose weight by exercising. She plans to run up and down the stairs in a football stadium as fast as she can a

### Water Jumped from Well

Having much difficulty with this word problem: A water well has an 8-inch diameter and is 175 feet deep. Assume that water enters the well at a rate of 4 gallons per minute and the pump works at a rate of 12 gallons per minute. If the water is 25 feet from the top of the well, determine the amount of work done in pumping it

### Friction, Motion and Work

A 920 N crate rests on the floor. How much work is required to move it at constant speed 5.40 m along the floor against a friction force of 176 N?

### Physics Questions

1. There is an analogy between rotational and translational physical quantities. Identify the rotational term analogous to each of the following linear quantities: acceleration, force, mass, work, translational kinetic energy, linear momentum, impulse. (Example: impulse F Delta-t corresponds to angular impulse, tau Delta-t . (Gr

### Physics Questions

1. (a) What is the momentum of a 1.20 x 10^4 kg garbage truck moving at 30.0 m/s? (b) At what speed would an 8.00 kg trash can have the same momentum? 2. One hazard of space travel is debris left by previous missions. There are several thousand masses large enough to detect by radar orbiting the earth, but there are far grea

### Solving for Force

Here is the problem: I don't understand what x and y in the force is for. Please show full solution A force F = (4x i + 4y j) N acts on an object as it moves in the x direction from the origin to x = 4.94 m. Find the work W = F · dr done on the object by the force.

### Frequency, Amplitude, Mass

A spring of force constant 4.0 N/m oscillates with a period of 1.0 sec. with a particular mass m attached. A total energy of 0.130 J is put into the spring-mass system. What is the frequency of the motion? Find the amplitude of the motion. Find the value of the mass, m. What is the speed of the mass when its displacement is 15.0

### Working with atwoods machine - acceleration of the masses

In an atwoods machine experiment, the larger mass is 1.8kg and the smaller mass is 1.2kg. Ignoring friction what is the acceleration of the masses when they are released from rest?

### Find Work Done for Constant Velocity

A 70 kg cart is pushed 50 m with a constant velocity upon a 45 degree friction less incline. Find the work done on the cart. Assume g=9.8m/s^2.

### Work done - A 100kg object is pulled upwards 5.0 meters by a rope...

A 100 kg object is pulled upwards 5.0 meters by a rope with an acceleration of 1.0 m/s^2. Find the work done by the tension force in the rope.

### Need some help on a take home assignment to

1, Three identical balls are thrown from the top of a building, all with the same initial speed. Ball 1 is thrown horizontally, ball 2 is thrown at some angle above the horizontal, and ball 3 is thrown at some below the horizontal. Rank the speed of the balls as they reach the ground from fastest to slowest. A,1-2-3 B,2-1-3

### Magnetism - Sliding mass with charge

A body of mass m and charge +q slides down a frictionless slope inclined at an angle theta to the horizontal. A magnetic field B is directed across the slope and into the paper as on the diagram. a) Draw a clear free-body diagram for the body as it moves with velocity v down the slope. Indicate all the forces acting on the ch

### Electric fields/ electric flux/ electric potential energy

1.The anode (positive terminal) of an X-ray tube is at a potential of +90 000 V with respect to the cathode (negative terminal). (a) How much work (in joules) is done by the electric force when an electron is accelerated from the cathode to the anode? (b) If the electron is initially at rest, what kinetic energy does the el

### Circuits with capacitators

The figure (attached) shows a simplified circuit for a photographic flash unit. This circuit consists of a 9.0 V battery, an R = 45.0 k resistor, a 140 µF capacitor, a flashbulb, and two switches. Initially, the capacitor is uncharged and the two switches are open. To charge the unit, switch S1 is closed; to fire the flash, sw

### Problems

(See attached file for full problem description and diagrams) --- 3. The filament of a light bulb has a resistance of 580 &#8486;. A voltage of 120 V is connected across the filament. How much current is in the filament? 13. A cylindrical copper cable carries a current of 1200 A. There is a potential difference of 1.

### Problems

Which is the correct answer. During an evening news broadcast in Helsinki, Finland, the meteorologist indicated that the day's lowest temperature was -4.0 °C. What is the corresponding value of this temperature on the Fahrenheit scale? A -7.2 °F B -4.0 °F C 17 °F D 25 °F E 39 °F Complete th

### Physics

Please help with a brief explanation for each of the following questions 1. If you fill a glass bottle with water and seal it tight and leave it in a hot car on a summer day, it will break (I can testify to this from personal experience!). Likewise, if you fill a glass bottle with water and seal it tight and put it in yo

### Dimensional Analysis for Pendulum

The period of a simple pendulum, defined as the time necessary for one complete oscillation, is measured in time units and is given by T=2pi sqrt(l/g) Where l is the length of the pendulum and g is the acceleration due to gravity, in units of length divided by time squared. Show that this equation is dimensionaly consistent. (

### Relative mass, gravitational force, and tension

(See attached file for full problem description) --- 1. An astronaut orbits the earth in a space capsule whose height above the earth is equal to the earth's radius. How does the mass of the astronaut in the capsule compare to her mass on the earth? A It is equal to her mass on earth. B It is equal to one-half of he

### Various Physics (Mechanics) Problems

(See attached file for full problem description) --- 37. A block whose weight is 45.0 N rests on a horizontal table. A horizontal force of 36.0 N is applied to the block. The coefficients of static and kinetic friction are 0.650 and 0.420, respectively. Will the block move under the influence of the force, and, if so, what wi

### Mathematical Conceptualization of Force, Mass, and Acceleration

A 810-kg car accelerates from rest to 27 m/s in a distance of 120 m. What is the magnitude of the average net force acting on the car? A 740 N B 2500 N C 91 N D 1300 N E 7900 N Two forces act on a 4.5-kg block resting on a frictionless surface as shown (see attached file). What is the magnitude of the

### Classical Mechanics - Speed of a Ferry and Parabolic Curve of a ball

A ferry can travel at an optimal speed of 8 km/h in still water measured relative to the shore. What is the optimal speed of the ferry, relative to the shore, if it moves perpendicular to a 6 km/h current? A 4 km/h B 8 km/h C 10 km/h D 14 km/h E 28 km/h A baseball is hit upward and travels along a pa

### Basic Math applications to Classical Mechanics

A park ranger wanted to measure the height of a tall tree. The ranger stood 6.10 m from the base of the tree; and he observed that his line of sight made an angle of 73.5° above the horizontal as he looked at the top of the tree. What is the height of the tree? A .5.84 m B 8.77 m C 11.7 m D 17.3 m E 20.6

### Kinematics in Two Dimensions

11. You are driving into St. Louis, Missouri, and in the distance you see the famous Gateway-to-the-West arch. This monument rises to a height of 192 m. You estimate your line of sight with the top of the arch to be 2.0° above the horizontal. Approximately how far (in kilometers) are you from the base of the arch? 21. A

### Mathematical Concepts

7. A tourist being chased by an angry bear is running in a straight line toward his car at a speed of 4.0 m/s. The car is a distance d away. The bear is 26 m behind the tourist and running at 6.0 m/s. The tourist reaches the car safely. What is the maximum possible value for d? 19. In getting ready to slam-dunk the ball, a

### Kinematics and Vector Questions

I need some help with these two physics questions on vectors: 33. An ocean liner leaves New York City and travels 18.0° north of east for 155 km. How far east and how far north has it gone? In other words, what are the magnitudes of the components of the ship's displacement vector in the directions (a) due east and (b) due