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    Kinetic and Potential Energy?

    Kinetic and Potential Energy!?! This problem is totally confusing me..can someone please explain it...:confused: A 3.0 kg object subject to a restoring force F is undergoing simple harmonic motion with a small amplitude. The potential energy U of the object as a function of distance x from...
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    Work/Spring problem

    The exact problem is: A massless spring is between a 1-kilogram mass and a 3-kilogram mass, but it is not attached to either mass. Both masses are on a horizontal frictionless table. In an experiment, the 1-kilogram mass is held in place, and the spring is compressed by pushing on the...
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    Work problem

    Ok...Here is the problem. A block of mass 4 kilograms, which has an initial speed of 6 meters per second at time t=0, slides on a horizontal surface. (a) Calculate the work W that must be done on the block to bring it to rest. For this problem, I used the formula W= 1/2mvf ^2– 1/2mvi ^2...
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    Velocity and Acceleration

    Ok, I have this problem... The first 10 meters of a 100 meter dash are covered in 2 seconds by a sprinter who starts from rest and acceleraties with a constant acceleration. The remaining 90 meters are run with the same velocity the stprinter had after 2 seconds. a) Determin the sprinter's...
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    Moment of inertia

    does anyone know an easier way to determine which formula is used for calculating moment of inertia? i have all the formulas and descriptions, but i have trouble figuring out which formula to use based on what is given in the problem. any ideas thatll help me?
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    Pool ball collision physics

    I swear, this is the last problem that I have. Here it goes... A pool ball having a mass of .65 kg experiences an elastic collision with a croquet ball having a mass of 1.38 kg. The pool ball had been rolling for 4.3 seconds, having covered a distance of 22.6 meters during that time. The...
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    Confused on velocity

    Here's my predicament... A 30.0 kg shopping cart full of groceries sitting at the top of a 2.0 meter hill rolls until it hits a tree stump at the bottom of the hill. Upon impact, a .25 kg can of peaches flies out of the cart. What is the velocity of the can as it leaves the cart? I tried...
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    Solving for time and displacement

    Ok, here's the problem that I am working on now. Sarah is walking at a speed of 1.5m/s when she accidentally slips on a patch of ice whose coefficient of kinetic friction is 0.060. If Sarah has a mass of 40.0 kg, how long before she comes to a stop on the ice? I'm stuck because I don't know...
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    Helicopter final velocity help

    Okay...I am think that I am totally lost on this problem. A helicopter holding a 70-kilogram package suspended from a rope 5.0 meters long accelerates upward at a rate of 5.2 m/s^s. When the upward velocity of the helicopter is 30 meters per second, the rope is cut and the helicopter...
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    Mouse trap cars

    Does anyone have any tips on how to make/build a mouse trap car, with the mouse trap being the only source of energy? I have an idea of what it should look like, and how it should work, but I'm really not sure. Is there any helpful hints that I might need while building my project for my physics...
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    Collisions of hockey pucks

    Okay, here's the problem I'm working on... A .50 kg hockey puck moving at a speed of 5.70 m/s collides with a stationary hockey puck of equal mass. After the collisions, the first puck moves off in a direction 60 degrees to the left of its original direction, while the second puck moves off at...
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    Naming Ionic formulas

    Okay, I am so confused about how to determine whether or not you have to use the parenthesis with the Roman numeral. It is confusing me because some of the compounds that I have to write the name for, are ternary compounds, and I'm not sure which order they go in. :confused:
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    Find the magnitude of the force that stops the bullet

    HELP Please!! Ok, I am totally lost on how to solve this problem: A 5 g bullet moving at 600 m/s penetrates a tree trunk to a depth of 4 cm. a. use work and energy considerations to find the magnitude of the force that stops the bullet b. assuming that the frictional force is constant...
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    Find the coefficient of kinetic friction problem

    Ok, here is my dilemma: A flight attendant pulls her 70.0 N flight bag a distance of 253 m along a level airport floor at a constant velocity. The force she exerts is 40.0 N at an angle of 52 degrees above the horizontal. Find the following: a) the work she does on the flight bag b) the work...
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    More energy is needed to walk down stairs than to walk horizontally

    Ok, here is my problem: Explain why more energy is needed to walk down stairs than to walk horizontally at the same speed? I don't get it, its against logic isn't it. Is it because of the height, that causes the energy walking down the stairs to be greater? That's the only explanation that I...
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    Negative or not?

    :confused: I know that you can have a negative acceleration, which would be considered deceleration, but is it possible to have a negative speed? It may sound like a stupid question to some people, but I am completely baffled.
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    How fast was the ball moving when it left the pool table?

    HELP!!! PlEaSe Okay, here is my problem: In a wild shot, Bo knocks a pool ball of mass of .85 kilograms offa 95-cm high pool table, and the ball hits the floor with a speed of 6.0 m/s. How fast was the ball moving when it left the pool table? I don't want to know the answer, I just want to...
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    Coefficient of Kinetic friction

    Ok, in this problem, I am given theta, which in 30 degrees, and acceleration, which is 1.2 m/s^2. How do I solve for the coefficient of Kinetic friction without the mass? :confused: