Two particles each of mass m, go around a circle of radius R under the action of their mutual gravitational attraction. Find the speed of each particle.

Two planets of mass 2 x 1025kg are release from rest 9.0 x 1012 m apart. What is the speed of the planets when they are half this distance apart?

A 1.8kg physics cart is initially traveling 2.8m/s when it collides with an ideal spring (with a spring constant of 710N/m and natural length shown. The final time is defined as when the spring at maximum compression and the cart is about to rebound backwards. Neglect loss. List the energy types at the initial and final time and whether work and loss (due to non- conservative forces) occur as well as the corresponding amounts of energy. 0.335m reference level initial: unit v wwww work? unit loss? unit final: unit wwww reference level How much did the spring's length change during the compression? unit What is the length of the spring at maximum compression? unit What is the spring force at this time? unit

Pick out the only vector quantity in the following list:  Temperature, pressure, impulse, time, power, total path length, energy, gravitational  potential, coefficient of friction, charge.

(a) What is the gravitational potential energy of a two-particle system with masses 6.8 kg and 3.0 kg, if they are separated by 1.7 m? If you triple the separation between the particles, how much work is done (b) by the gravitational force between the particles and (c) by you?

A man of mass 80.0 kg walks down the aisle of an airplane at a speed of 1.00 m/s in the forward direction while the plane moves at a speed of 300 m/s relative to the earth. Find the man’s kinetic energy relative to (a) the plane; (b) the earth.

The potential energy U in Joule of a particle of mass is 4kg moving in the x-y plane is givenby the formula U = 6x + 8y + 5. Here x and y are coordinates of the particle in meter.The particle is at (3,5) at t = 0 and v 0 = 0. i and jare the unit vectors across x and y axisrespectively.

Four protons, each with mass M and charge +e, are initially held at the corners of a square that is d on a side. They are then released from rest. What is the speed of each proton when the protons are very far apart?

.  An electron in a television tube is accelerated uniformly from rest to a speed of 8.4×107m/s over a distance of 2.5 cm. What is the power delivered to the electron at the instant that its displacement is 1.0 cm?

The three spheres in the figure, with masses mA = 79 g, mB = 7 g, and mc = 22 g, have their centers on a common line, with L = 21 cm and d = 4 cm. You move sphere B along the line until its center-to-center separation from C is d = 4 cm. How much work is done on sphere B(a) by you and (b) by the net gravitational force on B due to spheres A and C? (a) Number i (b) Number i B Units Units C ✪ ✪