A 292.0 kg rocket moving radially outward from Earth has a speed of 7.86 km/s when its engine shuts off 124 km above Earth's surface. A) Assuming negligible air drag acts on the rocket, find the rocket's kinetic energy when the rocket is 1000 km above the Earth's surface? B) What maximum height above the surface is reached by the rocket?

Protons and neutrons (together called nucleons) are held together in the nucleus of an atom by a force called the strong force. At very small separations, the strong force between two nucleons is larger than the repulsive electrical force between two protons--hence its name. But the strong force quickly weakens as the distance between the protons increases. A well-established model for the potential energy of two nucleons interacting via the strong force is U=U0[1−e−x/x0] where x is the distance between the centers of the two nucleons, x0 is a constant having the value x0 = 2.0 × 10−15 m, and U0 = 6.0 × 10−11 J. Quantum effects are essential for a proper understanding of nucleons, but let us innocently consider two neutrons as if they were small, hard, electrically neutral spheres of mass 1.67 ×10−27 kg and diameter 1.0 × 10−15 m. Suppose you hold two neutrons 9.0 × 10−15 m apart, measured between their centers, then release them.What is the speed of each neutron as they crash…

A couple of soccer balls of equal mass are kicked off the ground at the same speed but at different angles. Soccer ball A is kicked off at an angle slightly above the horizontal, whereas ball B is kicked slightly below the vertical. How do each of the following compare for ball A and ball B? (a) The initial kinetic energy and (b) the change in gravitational potential energy from the ground to the highest point? If the energy in part (a) differs from part (b), explain why there is a difference between the two energies.

Suppose that a spacecraft of mass 6.9 x 104 kg at rest in space fires its rockets to achieve a speed of 5.2 x 103 m/s. How much work has the fuel done on the spacecraft?

A man of mass 79.5 kg walks down the aisle of an airplane at a speed of 1.50 m/s in the forward direction while the plane moves at a speed of 325 m/s relative to the earth. (a) Find the man's kinetic energy relative to the plane.(b) Find the man's kinetic energy relative to the earth.

An object whose mass is 10 lb is projected straight upward from the surface of the earth and reaches a height of 100 ft when its velocity reaches zero. The only force acting on the object is the force of gravity. The acceleration of gravity is g = 32.2 ft/s². Determine the initial kinetic energy of the object, in ft·lbf, and the initial velocity of the object, in ft/s.

An athlete throws a 1.5 kg ball with a horizontal speed of 9 m/s, from a height of 4.8 metres above the ground.  a) Calculate the kinetic energy, gravitational potential energy and total mechanical energy of the ball at its starting position. b) Calculate the maximum speed attained by the ball, just as it reaches the ground's surface.