Because the force of Newtonian gravity is a central force, there is no torque on a satellite orbiting a planet: the force is always parallel to the position vector. Therefore, angular momentum is conserved always in Newtonian gravitation, provided there are no externally acting forces.

Explanation of how objects under the influence of gravity move in orbits. A body in uniform circular motion undergoes at all times a centripetal acceleration given by equation (40). According to Newton’s second law, a force is required to produce this acceleration.

The kinetic energy of a satellite in a circular orbit is half its gravitational energy and is positive instead of negative. When U and K are combined, their total is half the gravitational potential energy.

Flipping Physics Lecture Notes: Orbital Momentum Conservation Example: A satellite is in an elliptical orbit. So, linear momentum is not conserved for an object in an elliptical orbit. (b) Angular momentum is conserved when the net torque acting on the system equals zero: Again, the system is just the satellite.

Angular momentum is conserved for orbital systems.

Angular momentum is not conserved in a pendulum. When the pendulum is moving from the extreme position towards the center, gravity is exerting a torque which increases the angular momentum. Energy is conserved in a pendulum.

The law of momentum conservation can be stated as follows. For a collision occurring between object 1 and object 2 in an isolated system, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision.

If net external torque on a system is zero, then the angular momentum of the system can not change. If net external torque on a system is zero, then the angular momentum of the system remains same.

If the net torque on a rotatable object is zero then it will be in rotational equilibrium and not able to acquire angular acceleration.

In US mechanical engineering, torque is defined mathematically as the rate of change of angular momentum of an object (in physics it is called “net torque”). The definition of torque states that one or both of the angular velocity or the moment of inertia of an object are changing.

Any force that is along a line which passes through the axis of rotation produces no torque. Note that torque is a vector quantity, and, like angular displacement, angular velocity, and angular acceleration, is in a direction perpendicular to the plane of rotation.

So, a net torque will cause an object to rotate with an angular acceleration. Because all rotational motions have an axis of rotation, a torque must be defined about a rotational axis. A torque is a force applied to a point on an object about the axis of rotation.

An object in rotational equilibrium. The torque from normal force cancels the torque from gravity. The normal force acting on the pivot point can help support the object’s weight, but it can’t create a torque because it’s not applied at any distance away from the pivot.

Torque is the rotational equivalence of linear force. Speed measures the distance covered in unit time. The relation between torque and speed are inversely proportional to each other. The torque of a rotating object can be mathematically written as the ratio of power and angular velocity.

We are asked about the angular momentum of the satellite with respect to the centre of earth. We know that the equation for angular momentum is given by, →L=r×→p, where ‘L’ is angular momentum, ‘r’ is radius and ‘p’ is momentum.

Uniform circular motion A particle executing uniform circular motion. The uniform circular motion is characterized by constant speed. Hence, speed is conserved. As there is an external force on the particle, linear momentum (mv) is not conserved.

Angular momentum is conserved as long as no net torque is applied. This means we can apply angular momentum conservation. At all points in the orbit angular momentum is conserved – for an elliptical orbit as r increases the speed must be reduced to compensate for that, and vice versa.