Explore BrainMass


Laws of Motion: Friction

1. A dockworker is loading 20.2-kg crates onto a ship. He notices that it takes 77.2 Newtons of horizontal force to set them into motion from rest. Once in motion, it takes 58.3 Newtons of horizontal force to keep them moving at a constant speed. Determine the coefficient of static friction. Enter your answer accurate to the thi

Rate of acceleration and tension of wire in pulley problem

Please explain how to find acceleration of the system and tension of the wire in the following case: A mass (m=1.4kg) sits on a frictionless table. Another mass is connected to it by a wire over a frictionless pulley (mass of second object = 1.6kg). See attached file for figure.

Mechanics: 14 Questions about velocity, acceleration, force.

(See attached file for full problem description) --- As a vehicle goes from +4m/s to -1 m/s, what is its change in velocity? For 2 and 3 use the following: Vector P: 50 meters @ 110 degrees Vector Q: 35 meters @ 315 degrees Question 2: What is 3P - 3Q? Question 3: What is 2P + 3Q? Question 4: Dick Rutan,

Laws of Motion: Force, Tension and Acceleration

The sled dog in figure drags sleds A and B across the snow. The coefficient of friction between the sleds and the snow is 0.10. a.) If the tension in rope 1 is 150 N, what is the tension in rope 2? Answer: =? N

Atwood Machine Special Cases

I have no clue how to go about getting these equations. Can you help me out and explain how to do these. It is not for a test or anything. It is just a homework problem, but I can't figure it out. (See attached file for full problem description and equations) --- Atwood Machine Special Cases: An Atwood machine consist

Mass hanging from a rope

1. A mass is hung from ropes as shown in the diagram. The rope on the left has a tension T1 = 10.0 N. (A) Draw a free-body diagram of the knot where the three ropes meet. (B) Find the tension T2 in the right-hand rope. (C) Find the mass which is hanging. (Answers: T2 = 27.5 N, m = 2.98 kg.) 2. A 63.0 kg sprinter starts a

Newton's Law of Motion

A 20-kg child sits on a 5-kg sled and slides down a 125-meter, 31-degree slope, to the nearest m/s what is his or her speed at the bottom?

Newton's Law of Motion

A child pulls a wagon with a force of 37 N by a handle making an angle of 30 degrees with the horizontal. If the wagon has a mass of 4.5 kg, to the nearest hundredth of a m/s2 what is the acceleration of the wagon? To the nearest newton what would be the minimum force applied at that angle which would lift the wagon off the g

Newton's Law of Motion

The red box has a mass of 20 kg and the blue box has a mass of 11.1 kg and the Force is 220 N. To the nearest tenth of a m/s2, what is the acceleration of the combination? To the nearest newton what force does the blue box exert on the red box?

Losing Cargo Problem

I am working on a losing cargo problem. I have a box of mass 12.7kg that rests on the flat floor of my truck. My coefficents of friction between the box and floor are u8 =0.180 and uk=0.160. TMy truck stops at a stop sign and then starts to move with an acceleration of 2.15m/s2 . (That s squared.) So if the box is a distan

Tennis problem

At serve a tennis player aims to hit the ball horizontally. What minimum speed is required for the ball to clear the 0.89 m high net about L=14.8 m from the server if the ball is "launched" from a height of H=2.39 m?

Find an equation of motion and differentiate to find acceleration.

Please find details of problem on attached PDF file. I desperately need an answer to this problem straight away so if you cannot start working on an answer immediately please do not sign-out my problem. Thank you PS Please can you go through the steps required to transpose the equation clearly.

Forces and acceleration question

(See attached file for full problem description with diagrams) --- 63. Only two forces act on an object (mass = 4.00 kg), as in the drawing. Find the magnitude and direction (relative to the x axis) of the acceleration of the object... --- (See attached file for full problem description with diagrams)

Atwood machine & rotating rods questions

The first question involves an atwood machine, the second involves two different rods attached to hinges falling/rotating to the ground. See the jpeg for exact questions. The text is provided below simply for the benefit of the search engine: Atwood Machine A frictionless pulley with mass Mb is attached to the ceiling,

Mass of Planets, Gravitational Acceleration and Period of a Pendulum

Find the mass and the radii of the planets Mercury, Neptune and Pluto, masses in kilograms and radii in meters. With that data calculate the gravitational acceleration on each of the planets in kilograms and meters and show the gravitational acceleration in meters per square second. With the gravitational acceleration from abo

Stone launched vertically upward from top of cliff

1) Luigi launches a stone vertically upward from the top of a cliff. The height of the stone above the base of the cliff is appoximated by the model h=65+10t-5t^2 where t is time in second and h is height in metres a) how high is the stone above the base of the cliff after 3 seconds? h = 65 + 10t - 5t^2 h = 65 +10(3) -


1) In the drawing the rope and the pulleys are massless and there is no friction Find a) the tension in the rope, and b) the acceleration of the 12kg block. (The 12 kg block is on the table connected to a 3 kg block which is hanging off the table by a pulley) 2) A chain consisting of five links, each of mass 0.10k

Amplitude of weightlessness

An ant with mass is standing peacefully on top of a horizontal, stretched rope. The rope has mass per unit length and is under tension . Without warning, Throckmorton starts a sinusoidal transverse wave of wavelength propagating along the rope. The motion of the rope is in a vertical plane. What minimum wave amplitude will

Calculatin Angular Acceleration

Question: An ice skater rotates 2 revolutions per second. She puts her feet on the ground to generate a friction force so that she stops rotating in 20 sec. What is the angular acceleration in rad/s^2. How many rotations did the ice skater make before stopping?

Value of gravitational acceleration on moon

A pendulum of length 2 meters is taken to the moon. if this pendulum makes 10 oscillations in 32.0 seconds, what is the value of gravitational acceleration on this moon? a. 3.86 m/s^2 b. 2.54 m/s^2 c. 7.71 m/s^2 d. 9.86 m/s^2

Centripetal Acceleration

A centrifuge rotor is accelerated from rest to 20,000 rpm in 5.0 min: (a) What is the current angular speed (omega) in rad/sec? (b) What is the angular acceleration (alpha)rad/sec^2? (c) If the centrifuge is modeled as a cylinder of radius 0.10 m and mass 2.0 kg, what torque is applied to make it spin?

Uniform Circular Motion and Centripetal Acceleration

An ultracentrifuge operates at a speed of 5.00x10^6 rpm. It contains test tubes filled with viruses. (a) what is the centripetal acceleration on a virus at a radial distance of 4.00 cm from the centrifuge's axis of rotation? (b) How does this acceleration compare with g, the acceleration due to gravity?

Uniform Circular Motion and Centripetal Acceleration

The Moon revolves arond the earth in 27.3 days in a nearly circular orbit with a radius of 3.8 x 10^5 km. Assuming that the Moon's orbital motion is a uniform circular motion, what is the Moon acceleration as it "falls" toward the earth?

Linear Momentum and Collisions - Acceleration and Time

A horizontal force of 100 N is applied to a 50.0 kg box; the box slides on a level floor and is opposed by frictional force of 20 N. Show the algebraic steps a) What is the acceleration of the box? b) How long does it take to move 5.0 meters? c) What is its speed at this point (5.0 meters)?