Y; = h Ugi = mgh K; = 0 gi = y Ug = mgy 1 h y y = 0 U= 0 Figure 8.4 (Example 8.2) A ball is dropped from a height h above the ground. Initially, the total energy of the ball- Earth system is gravitational potential energy, equal to mgh relative to the ground. At the position y, the total energy is the sum of the kinetic and potential energies.
Rigid Body
A rigid body is an object which does not change its shape or undergo any significant deformation due to an external force or movement. Mathematically speaking, the distance between any two points inside the body doesn't change in any situation.
Rigid Body Dynamics
Rigid bodies are defined as inelastic shapes with negligible deformation, giving them an unchanging center of mass. It is also generally assumed that the mass of a rigid body is uniformly distributed. This property of rigid bodies comes in handy when we deal with concepts like momentum, angular momentum, force and torque. The study of these properties – viz., force, torque, momentum, and angular momentum – of a rigid body, is collectively known as rigid body dynamics (RBD).
A ball of mass m is dropped from a height h above the ground as shown.
(A) Neglecting air resistance, determine the speed of the ball when it is at a height y above the ground. Choose the system as the ball and the Earth. (B) Find the speed of the ball again at height y by choosing the ball as the system.
Trending now
This is a popular solution!
Step by step
Solved in 2 steps with 2 images
