Mechanical energy Definition and 354 Threads

I'm pretty new to physics. It has always fasinated me. I've had this idea floating around in my head for quite some time. Maybe someone could point me in the right direction. An electric motor converts electrical energy into mechanical energy. An alternater converts mechanical energy into...

Homework Statement Particle A and partidcle B are held together with a compressed spring between them. When they are released, the spring pushes them apart, and they then fly off in opposite directions, free of the spring. The mass of A is 3 times the mass of B, and the energy stored in the...

Homework Statement A 1200-kg car traveling initially with a speed of 25.0 m/s in an easterly direction crashes into the rear end of a 9000-kg truck moving in the same direction at 20.0 m/s. The velocity of the car right after the collision is 18.0 m/s to the east. (a) What is the velocity of...

Question: An object has a mass of M ... it explodes up into two pieces.. one piece has a mass of M/3 and the other piece has a mass of 2M/3. 1. which object has larger l momentum l ? ... both have same 2. which object has larger speed ? ... smaller mass has larger speed 3. which object...

Good day, I found this question on the Web. A piston in an engine moves back and forth over a distance of 2mm in SHM with a frequency of 120Hz. Find the total mechanical energy. Is there a way to find the energy without knowing the piston's mass? The answer provided is 14 \mu~J...

A railroad car of mass 2.49 104 kg, is moving with a speed of 3.89 m/s. It collides and couples with three other coupled railroad cars, each of the same mass as the single car and moving in the same direction with an initial speed of 1.95 m/s. (a) What is the speed of the four cars after the...

So I have a quick question that I got in my physics class and I'm not to informed on Mechanical energy so if you could help me out that would be great: Which of following is/are true regarding the principle of mechanical energy? I. An object moves uphill with a decreasing speed II. An...

Hey guys. Could someone please explain orbital decay to me, with reference to the kinetic energy lost, and stuff like that. Also i would like to know how the equation for mechanical energy in orbits is derived, and how it is used. Thanks!

a runaway truck with failed brakes is moving downgrade at 150km/h (41.6 m/s) just before the driver steers the truck travel up a frictionless emergency escape ramp with an inclination of 15°. The truck's mass is 5000 kg. What minimum length L must the ramp have if the truck is to stop...

in, for example a hand cranked generator, or even a hydrocarbon based generator, when there is no ionisation/ oxidation-reduction going on to produce the electrons... where are they coming from? i know how such a generator is physically put togther, but where are the electrons coming?

Hello homework forum, I am working on some mechanical energy questions right now for Physics class, and I have a quick question. A mass (1.00 kg) is projected vertically upwards at a speed of 40.0 m/s. There is a frictional force of 5.0 N acting on the mass. The question that's bothering me...

My physics class is currently invovled with a project regarding conservation of mechanical energy. I will need to choose or create a model that will demonstrate conservation of mechanical energy, then analyze the model and explain it. Does anyone know of any model that can be made easily...

an object moves from A to B only two forces act on it. one force is conservative and does -70J of work, the other force is nonconservative and does +50J of work. kinetic energy of the object decreases and mechanical energy decreases, right?

A small car has an initial speed of 4.0m/s just before it enters a loop. What is the largest value for r (radius) that the loop can have if the car is to remain in contact with the circular track at all times? Answer: r = 0.327m What I tried was; before the car enters the loop it posses pure...

Mechanical Energy! Help! a 30 g bullet, with a horizontal velocity of 500m/s, comes to a stop 12 cm within a solid wall. (a)what is the change in it's mechanical energy? (b)what is the magnitude of the average force from the wall stopping it? * this is the first problem I've done like...

A 991kg car traveling initially with a speed of 32.2m/s in an easterly direction crashes into the rear end of an 8650kg truck moving in the same direction at 17.8m/s. The velocity of the car right after the collision is 10.4m/s to the east. How much mechanical energy is lost in the collision...

I can't copy the pictures but here's a "reproduction" of one: Wall----------box (There's a spring attached to both the wall and the box.) The box is resting on a frictionless surface. The spring has been stretched to the right by a distance given and it's about to be released. It will...

The questions read... 1.) An Olympic runner leaps over a hurdle. If the runner's initial vertical speed is 2.2 m/s, how much will the runner's center of mass be raised during the jump? 2.) A pendulum bob is released from some initial height such that the speed of the bob at the bottom of...

The figure above shows three choices for the orientation of a plane that is not frictionless, and for the direction in which a block slides along the plane. The block begins with the same speed in all three choices, and slides until the kinetic frictional force has stopped it. For which choice...

is it true that the total mechanical energy of a system is equally divided between kinetic energy and potential energy?

In preparation for shooting a ball in a pinball machine, a spring (k = 675 N/m) is compressed by 0.0650 m relative to its unstrained length. The ball (m = 0.0585 kg) is at rest against the spring at point A. When the spring is released, the ball slides (without rolling) to point B, which is...

Help! I don't understand how to do this problem: A basketball of mass 0.50 kg is dropped from rest from a height of 1.22 m. It rebounds to a height of 0.40 m. (a) How much mechanical energy was lost during the collision with the floor? (b) A basketball player dribbles the ball from a...

I have two questions I'm a bit confused on... 1st: Ten days after it was launched toward Mars in December 1998, the Mars Climate Orbiter spacecraft (mass 629 kg) was 2.87 \times 10^{6} km from the Earth and traveling at 1.20 \times 10^{4} km/h relative to the earth. a.) At this time...

A crate of mass 10.0 kg is pulled up a rough incline with an initial speed of 1.50 m/s. The pulling force is 100 N parallel to the incline, which makes an angle of 20 degrees with the horizontal. The coefficient of kinetic friction is 0.400, and the crate is pulled 5.00 m. How much mechanical...

Hey guys! I am thoroughly confused.Hope u can help me. :smile: Can we say that living things have mechanical energy? Is muscular energy also mechanical energy? Can mechanical energy be equal to potential energy?If so, why is the definition "energy of a moving object is mechanical energy"...

Hey, Stuck on finding the mechanical energy of a mass-spring system, my question is as follows > A mass-spring system oscillates with an amplitude of .026 m. The spring constant is 290 N/m and the mass is 0.50 kg, it asks for the mechanical energy in (J). and the maximum acceleration of the...

A 30 g bullet, with a horizontal velocity of 516 m/s, stops 19 cm within a solid wall. (a) What is the change in its mechanical energy? (b) What is the magnitude of the average force from the wall stopping it? For Part a, To find the change in mechanical energy, do I use the equation...

I just can't seem to derive the correct formula for this one. A spring with k=40.0 N/m is at the base of a frictionless 30 degree inclined plane. A 0.50 kg object is pressed against the spring, compressing in 0.3m from its equilibrium position. The object is then released. If the object is...

Question image: http://people.mail2me.com.au/~benogorancic/que.JPG I have been trying to figure this out all day long and finally got these two answers. Part A: K = 5/2 * mgr Part B: h_min = 5/2 * R Could someone please confirm if I have the right answer and actually got the...

Question: A damped harmonic oscillator loses 5.0 percent of its mechanical energy per cycle. (a) By what percentage does its frequency differ from the natural frequency \omega_0 = \sqrt{k/m}? (b) After how may periods will the amplitude have decreased to 1/e of its original value? So, for...

A 19 kg box starts at rest and slides down a frictionless ramp. The length of the ramp is 4.5 m and the height above the ground at the top is 1.3 m. How fast is the box moving at the bottom of the ramp? Unsure of inclined planes...help with formulas, etc.?

How much work was required to push a 36 kg box from the bottom of a ramp a distance of 10 m to the top of 1.7 m above the ground if the friction force between the box and the ramp is 20 N? Help? Formulas?

help I'm really stuck on this question! A skier starts from rest at the top of a hill. The skier coasts down the hill and up a second hill. The crest of the second hill is circular, with a radius of r = 45 m. Neglect friction and air resistance. What must be the height h of the first hill so...

is mechanical energy conservative?

a 55 kg high jump athlete leaps into the air in attempt to clear the bar, at the top of the leap the athlete has a total mechanical energy of 3x10 to the power of 10 joules and is moving at 8.33m/s. Calculate the gravitational potentional energy. what the hell? how do i get my height...

I am having problems with this question. I keep getting an answer of 1.87m/s but the answer is 1.47m/s. A glider of mass .150kg moves on a horizontal frictionless air track. It is permanently attached to one end of a massless horizontal spring, which has a force of constant of 10 N/m both...

I have a problem for the subject in the title. I'm not really sure where to start, and I can't figure it out. In her hand a softball pitcher swings a ball of mass .250 kg around a vertical circular path of radius 60.0 cm before releasing it from her hand. The pitcher maintains a component...

TA Chuck Margraves spends his spare time bungee jumping off the Henley Street bridge. He has a 14 ft long bungee cord (unstretched) that has a spring stiffness of 22 lb/ft. To test his bungee, Chuck ties the bungee cord to the bridge railing, ties the other end to an unnamed EF professor...

A 2.00-kg ball is attached to the bottom end of a length of fishline with a breaking strength of (44.5 N) The top end of line is held stationary. The ball is released from rest with the line taut and horizontal (theta=90.0). At what angle theta(measured from the vertical) will the fishline...

A 60kg bungee jumper jumps from a bridge. He is tied to a 12m-long bungee cord and falls a total of 31m a) calculate the spring constant of the bungee cord b) calculate the maximum acceleration experienced by the jumper okay I'm stuck on b) I got a0 calculated without any problems at all...

I watched [Lecture 13] of the Newtonian Physics class in http://ocw.mit.edu/OcwWeb/Physics/8-01Physics-IFall1999/VideoLectures/index.htm . On the last part of the lecture, they did 2 experiments on pendulums (conservation of mechanical energy, etc.) and the first experiment followed the...

Greetings all :wink: I'm new to this forum, so please spare me if I make a fool of myself in this post. I was working on a Physics Practical this morning at school concerning Change in Mechanical Energy, in relation to Potential and Kinetic Energy. Although it seems like a easy task, I'm...

A pendulum of length 150cm swings with an amplitude of 1.8cm. Its mechanical energy is 6mJ. What is the mechanical energy of the same pendulum when it swings with an amplitude of 4.3cm? The answer is supposed to be in mJ. How do I relate the mechanical energy to what they gave me in the...

Hi, this is my first time here and Id like to thank in advance for any help offered :smile: Im having trouble with the following question about 2 masses in an atwoods machine. 2 masses are initially at rest at the same height, if m2 has a given initial upward speed, how high does m2 rise...

ok, heres the prob: A 21.0 kg cannon ball is fired from a cannon with a muzzle speed of 1100 m/s at an angle of 37.3° with the horizontal. A second ball is fired at an angle of 90.0°. Use the law of conservation of mechanical energy to find (b) the total mechanical energy at the maximum...

Several children, pretending they are playing in the jungle, suspend a rope from an overhead tree limb. A child of mass 40 kg running at 8.0m/s grabs the rope and swings off the level ground. a) What maximum height does the child reach? b) How fast would a 30 kg child have to run to reach...

[urgent] simple mechanical energy question [gr.11] Several children, pretending they are playing in the jungle, suspend a rope from an overhead tree limb. A child of mass 40 kg running at 8.0m/s grabs the rope and swings off the level ground. a) What maximum height does the child reach...

Hello, I've got a problem I've got stuck with. Anyone who can help me solve this? A 4kg block hangs by a light string that passes over a massless, frictionless pulley and is connected to a 6kg blovk that rests on a shelf. The coeff of kinetic friction is 0,2. The 6kg block is pushed against a...

This is something I am learning on my own. However, this problem is confusing me: Red is a girl of mass m who is taking a picnic lunch to her grandmother. She ties a rope of length R to a tree branch over a creek and starts swing from rest at point A, which is a distance R/2 lower than the...

Is mechanical energy always conserved? Explain how this does not violate the law of conservation of energy by an example.