Explore BrainMass


Force Vectors and Work

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.

Work, energy, impulse, and momentum

A 464-kg hot-air balloon takes off from rest at the surface of the earth. The nonconservative wind and lift forces take the balloon up, doing 195000 J of work on the balloon in the process. At what height above the surface of the earth does the balloon have a speed of 8.94 m/s? A person is making homemade ice cream. She exert

Cyclist's speed at crest of hill & frictional force on motion

A 82.3-kg skier rides a 2860-m-long lift to the top of a mountain. The lift makes an angle of 16.6° with the horizontal. What is the change in the skier's gravitational potential energy? A cyclist approaches the bottom of a gradual hill at a speed of 28.7 m/s. The hill is 8.84 m high, and the cyclist estimates that she is go

Work and energy: work done on a basketball by air resistance

A 72.0-kg man is riding an escalator in a shopping mall. The escalator moves the man at a constant velocity from ground level to the floor above, a vertical height of 3.70 m. What is the work done on the man by (a) the gravitational force and (b) the escalator? A 82.8-g arrow is fired horizontally from rest. The bowstring exe

Work, Kinetic Energy, and Acceleration

Please do the circled problems. Thanks. Questions: 89. Two particles with charges Q and -Q are fixed at the vertices of an equilateral triangle with sides of length a. If ..., the work required to move a particle with a charge q from the other vertex to the center fo the line joining the fixed charges is... Please se

Charge and Work

Please help me with the circled problems. Questions: 87. Points R and T are each a distance f from each of the two particles with charges of equal magnitudes and opposite signs as shown. If ... the work required to move a particle with the negative charge q from R to T is .... Please see the attached for the complete se

Charges, spherical shell, and charge density

Please show all work and show all equations used and diagrams, etc. etc. so I understand completely please. 1) Charge is placed on the surface of a 2.7cm radius isolated conducting sphere. The surface density charge is uniform and has the value 6.9*10^-6C/m^2. The total charge on the sphere is: 2) A spherical shell has a

Electrostatic Forces and Movement of Charged Particles

Please show all work and diagrams plus equations used to solve problem. Thanks! 1) Particles 1, with charge q1 and 2, with a charge q2 are on the x axis, with particle 1 at x = a with and particle 2 at x=-2a. For the net force on a third charges particle, at the origin to be zero q1 and q2 must be related by q2=: (answer B

Object Charges and Forces

Please show all work and diagrams plus equations used to solve problem. Thanks! 1) A small object has charge Q. Charge q is removed from it and placed on a second small object. The two objects are placed 1 meter apart. For the force that each object exerts on the other to be a maximum, q should be: 2) Two small charged

Working with harmonic wave functions

Write an expression for a harmonic wave with an amplitude of 0.11 m, a wavelength of 2.5 m, and a period of 1.2 s. The wave travels to the right.

Charged particles and net electrostatic force

Please show step by step solution you used to solve this problem and give the answer. Leave no details out! Even simple math! 1) The figure shows four situations in which five charged particles are evenly spaced along on an axis. The charge values are given except for the central particle, which has the same charge in all

Perturbation of a Negative Potential Time Dependent Problem

I am trying to calculate the probability that the n = 3 state will be excited at t = infinity for the case where b<<< a. and to show that for any value of b only the odd n states will be excited at t = infinity. My initial conditions and setup are: V(x,t) = Vinit(x) exp(-lambda times t) where I have a negative potential

Relativistic Momentum

A football player with a mass of 88 kg and a speed of 2.0 m/s collides head-on with a player from the opposing team whose mass is 120 kg. The players stick together and are at rest after the collision. Find the speed of the second player, assuming the speed of light is 3.0 m/s.

Spring Compression, Speed and Distance

6. [SJ3 7.P.024.] A toy cannon uses a spring to project a 5.30 g soft rubber ball. The spring is originally compressed by 5.00 cm and has a force constant of 7.80 N/m. When it is fired, the ball moves 16.0 cm through the horizontal barrel of the cannon, and a constant frictional force of 0.0320 N exists between barrel and ball.

Energy - Force and Work

A 90g bullet is fired from a rifle having a barrel 0.690m long. Assuming the origin is placed the bullet begins to move, the force (in newtons) exerted on the bullet by the expanding gas is 1000 + 6000x- 35000x*x where x is in meters. a) Determine the work done by the gas on the bullet as the bullet travels the length of the

The coordinates of the third mass ...

The center of mass of three objects is located at (1,0). One object with a mass of 5 kg is at (-2,-1) and a second object with a mass of 2 kg is at (0,0). Find the coordinates of the third mass of 3 kg. a.(1.7, 6.7) b.(2, 6) c. (1.3, 5.3) d. (6.7, 1.7)

Working with rotatinal inertia of a cylinder

A solid cylinder of mass 8kg and diameter 20cm is rotated about an axis parallel to its central axis at a distance of 10 cm from the cylinder. the rotatinal inertia of the cylinder about the parallel axis is: a. 0.12 kg m^2 b. 0.08 kg m^2 c. 12 kg m^2 d. 0.04 kg m^2

Rotational Work and Kinetic Energy

If the work required to spin a disk up from 1.0 rad/s to 2.0 rad/s is 100.0 J. (a) what is the moment of inertia (I) of the disk? (b) How much additional work would be required to increase its angular speed from 2.0 rad/s to 4.0 rad/s?

Rotational Work and Kinetic Energy - Speed and Height

A steel ball rolls down an incline into a loop-the-loop of radius R. (a) What minimum speed must the ball have at the top of the loop in order to stay on the track? (b) At what vertical height (h) on the incline, in terms of the radius of the loop, must the ball be released in order for it to have the required minimum speed at t

Work Done on a Cart

A 70 kg cart is pushed 50m with a constant velocity upon a 45 degree frictionless incline. Find the work done on the cart (assume 10 m/s^2 gor gravity). Express in scientific notation and in joules.

Work and Energy - Force of Friction and Kinetic Friction

Question: A box of mass m = 20.0 kg is pushed at a constant speed of v = 2.5 m/s, and by a force F = 25.0 N along the horizontal plane. Show the algebraic steps: a) What is the force of friction between the box and the surface? b) What is the value of the coefficient of kinetic friction?

Work Energy Theorem

If the work required to speed a car up from 1.0 m/s to 4.0 m/s is 6000J, what is the mass of the car? How much additional work would be required to increase its speed from 4.0 m/s to 10.0 m/s?

Work and Energy

A boy pushes a lawn mower on a level lawn with a constant force of 540N at an angle of 30 degrees to the horizontal. Show the algebraic steps. How far does the boy push the mower in 2500J of work?

Work and Force

A spring with spring constant k= 1550 N/m is compressed by 0.020m, specify magnitude and direction algebraically: a) What force is required to do this? b) How much work is done in compressing the spring? c) What is the potential energy stored in the spring?

Word and Energy of Dropping a Book

A student lifts a book of mass 1.12 kg to a height of 1.24 m; use g=9.8 m/s^2, write an equation then calculate: a) How much work does the student do? b) What is the potential energy of the book? c) If the student drops the book vertically, what is the book's kinetic energy when it reaches the floor? d) What is the spe

Simple Physics

A 615 kg car was involved in an accident. The accepted coefficient of friction between concrete and rubber is 0.65. The skid marks left by the car are 18.6m long. How was was the car moving when it hit the brakes?