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Energy

Spring action

"The launching mechanism of a toy gun consists of a spring of unknown spring constant. If the spring is compressed a distance of 0.139 m and the gun fired vertically, the gun can launch a 25.1g projectile from rest to a maximum height of 24.5 m above the starting point of the projectile. Neglecting all resistive forces, determin

KE, average speed

"A 48.5 kg student climbs a 5.90 m long rope and stops at the top. What must her average speed be in order to match the power output of a 140 W lightbulb?" Here's how I approached this problem: Since 1 W = 1 J/s, I set KE = 140 J. Then, v^2 = KE/((.5)m) = 140/24.25 = 5.77 Then v = 2.4 m/s But that's not the right an

The highest position the car reaches at the bottom of the hill

A 750 kilogram automobile is moving at 20.0 meters per second at a height of 5.0 meters above the bottom of the hill when it runs out of gasoline. The car coasts down the hill and then continues coasting up the other side unitl it comes to rest. Ignoring frictional forces and air resistance, what is the value of "h", the highes

Lifetime and energy uncertainty

The lifetime of a molecule in a certian electronic state is 10e-10 s. What is the uncertianty in energy of this state? Give the answer in J and in J/mol.

A compressed spring flings a stone upward when released. Find the maximum height.

SEE ATTACHMENT #1 for a diagram of parameters of the event. A spring is .66 m long when it contains no energy When a stone with mass M= 8.5 kg is placed on the spring it shortens by b= .06 m then supports the stone in equilibrium. The stone is now pushed down an additional d= .38 m. When released, the stone is projected up

Speed of particle on an incline

A small particle slides along a frictionless wire. If the particle's speed at point A is 8.85m/sec how fast is it moving at point B if it must go up a 2m incline?

Speed

A stone is dropped from a height of 100m. At what height is half of its energy potential and half kinetic? What is the speed of the stone at this height?

Power Output

Approximately 4X10^9kg of matter is converted into energy each second in the sun. Find the power output of the sun.

Electrons: Bohr model of the atom

PART ONE: According to the Bohr model of the atom, an electron cannot move from a lower energy orbit into a higher energy orbit: A) abruptly B) spontaneously C) unless it gains exactly enough energy D) unless it loses exactly enough energy PART TWO: No two electrons in an atom can have the same: A) orbit

Power, voltage and capacitor problem

1) A tungsten filament has a resistance of 3 OMP at 20 degrees. When connected to a 100V power supply a current of 6.0A passes through a filament. If the filament is connected to the same power supply when it is at 2000 degrees, what will be the current through the filament and its power loss? 2) A battery whose emf i

Conservation of energy; rotational kinetic energy

See attached file. A cart consists of a body of mass M mounted on two uniform cylinders, each mass m, radius R. The cart is moving at velocity V at its initial location on a plane inclined at angle b. SEE ATTACHMENT #1 for a diagram showing parameters. Known values are: M=2.1 kg, m=1.8 kg, angle b= 53 degrees, V= 2.5 m/sec.

Displacement of a beam of Hydrogen ions subjected to magnetic and electric fields.

A uniform electric field of 1.6 x 10^3 V/m and a uniform magnetic field of 3.34 x 10^-3 Wb/m^2 are parallel to each other and are acting along the Z-direction. A beam of Hydrogen ions of energy 150 eV is released in the X direction. A photographic plate is placed normal to the motion of the ions at a distance of 0.5m from the or

Physics: Velocity of the ball assuming mechnaical energy is conserved

A plank of length 2l and mass M lies on a frictionless plane. A ball of mass m and speed Vo strikes its end (the plank is standing vertical and the ball strikes the top from the left). Find the final velocity of the ball, Vf, assuming that mechanical energy is conserved and that Vf is along the original line of motion. b)Fin

Yo-yo Tension and Average Force on the String

A yo-yo of mass M has an axle of radius b and a spool of radius R. Its moment of inertia can be taken to be MR^2/2 and the thickness of the string can be neglected. The yo-yo is released from rest. a) What it the tension in the cord as the yo-yo descends and as it ascends? b) The center of the yo-yo descends distance h be