Explore BrainMass


What is the mass ratio of the boxes?

Two boxes are seen to accelerate at the same rate when a force F is applied to the first box and 4F is applied to the second box. What is the mass ratio of the boxes?

Motion on a circular path. (horizontal and vertical)

1. The tub of a washer goes into its spin-dry cycle, starting from rest and reaching an angular speed of 3.0 rev/s in 7.0 s. At this point the person doing the laundry opens the lid, and a safety switch turns off the washer. The tub slows to rest in 10.0 s. Through how many revolutions does the tub turn during this 17 s interval

Problem Set

(See attached file for full problem description) --- 2. The leg and cast in Figure P4.18 weigh 270 N, with the center of mass as indicated by the blue arrow in the diagram. The counterbalance w1 weighs 135 N. Determine the weight w2 and the angle needed so that no force is exerted on the hip joint by the leg plus cast.

Rotational Dynamics/angular acceleration using a turntable for the experiment

The claim that the acceleration of the falling mass is the same as the tangential acceleration of a point at the lever arm distance from the axis is : a = (r)(alpha), where a is the acceleration of the falling mass, r is the lever arm distance, and alpha is the angular acceleration of the turntable. Why is this claim valid? Use

What does the scale read during the acceleration of a moving elevator?

A person stands on a scale in a moving elevator and her mass is 60.0 kg and the combined mass of the elevator and scale is an additional 815 kg. Starting from rest, the elevator accelerates upward. During the acceleration, the hoisting cable applies a force of 9410 N. What does the scale read during the acceleration?

Vectors and force: Speed of car in wind

I wanted some help w/ a vector hypothetical. Say, there's is a wind, coming from the northwest (and going southeast), blowing at 25 to 30 MPH on a vehicle traveling east at 55MPH, say at 30 degree to the vehicle, a positive force on the back and left side of this vehicle. What formula would you use to should this positive force?

Angular speeds in radians, linear speeds and average angular acceleration. 9/5

A pneumatic high-speed cutter with a 7.50 cm diameter cutting disc is advertised to have a rotation rate of between 5,000 and 18,000 rev/min. A) What is the range of angular speeds in radians? B) What is the range of linear speeds of the edge of the disk? C) What is the average angular acceleration if, starting from rest

A sky diver in free fall travels at a speed...

10. A sky diver in free fall travels at a speed modeled by (see equation in attached file) ft per second after t seconds. How long will it take for the skydiver to attain the speed of 60 mph (note: 60 mph = 88 ft/sec)?

Cable supporting a boom & a sphere rolling down an incline

26) A 1200 N uniform boom is supported by a cable; one end of the cable being attached to a wall and the other end to top of the boom. The cable is perpendicular to the boom. One end of the boom is attached to a hing on the ground and is leaning away from the wall at an angle of 65 degrees to the ground. A 2000 N weight hangs f

Circular Motion: Centripetal Acceleration and Minimum Force

Please identify all variables used. 1) An engine flywheel initially spinning 2000 rpm has an angular acceleration of -10 rad/s2 as it slows down. How long does it take for the flywheel to turn through 100 revolutions? How long does it take to stop? 2) A 50 kg child stand at the rim of a merry go round with a radius of 2.

Masses, cord and pulley

A 4.78 kg mass (m2) is connected by a light cord to a 2.04 kg mass (m1) on a smooth surface. The pulley rotates about a frictionless axle and has a moment of inertia of 0.520 kg*m^2 and a radius of 0.350 m. 1.) Assuming that the cord does not slip on the pulley, find the acceleration of m1. 2.) What is the acceleration o

Average Angular Acceleration

Compact Disc. A compact disc (CD) stores music in a coded pattern of tiny pits 10^(- 7) m deep. The pits are arranged in a track that spirals outward toward the rim of the disc; the inner and outer radii of this spiral are 25.0 mm and 58.0 mm, respectively. As the disc spins inside a CD player, the track is scanned at a constant

Constant Acceleration Problem

Constant Acceleration Problem A motorist traveling with a constant velocity of 15 m/s passes a school-crossing corner. Just as the motorist passes, a police officer stopped on the corner starts off in pursuit with constant acceleration of 2.5 m/s^2 until her speed is 20 m/s. Then she slows down at a constant rate until she c

Potential Energy and Energy Conversion

Riding a Loop-the-loop. A car in an amusement park ride rolls without friction around the track shown in the figure. It starts from rest at point at a height above the bottom of the loop. Treat the car as a particle. 1. What is the minimum value of (in terms of) such that the car moves around the loop without falling off at t

Newton's Law (5.120)

(See attached file for full problem description with diagram). Moving Wedge. A wedge with mass rests on a frictionless horizontal table top. A block with mass is placed on the wedge (the figure a). There is no friction between the block and the wedge. The system is released from rest. 1. Calculate the acceleration of the

Concept of Psuedo Force

A 12.0-kg box rests on the flat floor of a truck. The coefficients of friction between the box and floor are : static = 0.19 and kinetic =0.15. The truck stops at a stop sign and then starts to move with an acceleration of 2.20 m/s^2. 1. If the box is 1.80 m from the rear of the truck when the truck starts, how much time elap

Newton's Law: Force, velocity, acceleration, and reaction.

A 4.9-N hammer head is stopped from an initial downward velocity of 3.2 m/s in a distance of 0.45 cm by a nail in a pine board. In addition to its weight, there is a 15-N downward force on the hammer head applied by the person using the hammer. Assume that the acceleration of the hammer head is constant while it is in contact wi

Newton's Second Law and Inclined Planes

(See attached file for full problem description with diagram and equations) --- The acceleration of a block of mass that is pulled up a frictionless plane inclined at angle with respect to the horizontal by a perfect string that passes over a perfect pulley to a block of mass that is hanging vertically. Visualize th

11 Newton's Laws Problems: Force, motion, acceleration, FBD,

Please solve each problem step by step giving solutions please. SHOW every equation used and every step getting to the answer. Show substitutions, etc. Please give units. Look below for pages. Adult student learning from ya'll and so you can read what I need help with I cut and paste the questions cause some cannot read m

Vertical Acceleration

A 5.5 kg object hangs at one end of a rope that is attached to a support on a railroad boxcar. When the car accelerates to the right, the rope makes an angle of 24 degrees with the vertical the acceleration of gravity is 9.8 m/s^2 : Find the acceleration of the car. (Hint: aobject = acar) Answer in units of m/s^2. Pictur

Uniform electric field: point charge and potential difference

Location A is 4 m to the LEFT of a point charge of 0.3 μC. Location B lies on the same line and is to the RIGHT of the charge. The potential difference VB - VA = 100 V. How far is Location B from the point charge? A uniform electric field has a magnitude of 2 x 103 N/C. In a vacuum, a proton begins with a speed of 4 x 1

Application of Bernoulli's theorem..

Problem 1 : Here is a cup with two holes (see attachment). The cup is filled with water to the top and the water is coming out of the holes. Assuming suitable values for heights, radius's etc. please answer the following questions : 1) Velocity with which the stream of water comes out. 2) Acceleration of the stream of w

Acceleration Calculation

A lunar lander is making its descent to Moon Base I. The lander descends slowly under the retro-thrust of its descent engine. The engine is cut off when the lander is 5.0 m above the surface and has a downward speed of 0.8 m/s. With the engine off, the lander is in free fall. What is the speed of the lander just before it to

Calculating acceleration and time of a jet

The catapult of the aircraft carrier USS Abraham Lincoln accelerates an F/A-18 Hornet jet fighter from rest to a takeoff speed of 173 mi/h in a distance of 307 ft. Assume constant acceleration. 1) Calculate the acceleration of the fighter in m/s2 2) Calculate the time required for the fighter to accelerate to takeoff speed

Motion in Plane: Rocket Lanching and Then Projectile Motion

See the attached file. A rocket accelerates upward from the ground at 25m.s-2 for 2.5s at an angle of 80o to the horizontal. The rocket motor stops and it eventually falls to the ground. Neglecting air resistance and assuming that the trajectory during acceleration is a straight line. a. Make a labeled sketch of the rocke

Calculating vertical displacement

See the attached file for the full problem description. Two basketball players are essentially equal in all respects (they are the same height, they jump with the same initial velocity, etc...). In particular, by jumping they can raise their centers of mass the same vertical distance, H (called their "vertical leap"). T

Projectile Motion of a Baseball Thrown

A teacher, 2.256 m tall, throws a basketball towards the hoop which is at a horizontal distance l. The basketball is thrown from the level of the teachers head or again 2.256 m at a velocity of 18 m/s, at an angle of 62 degrees from the horizontal. The height of the hoop 3.048 m. 1) Neglecting air friction, how long does