mechanics problem - rolling

A uniform rigid disk of radius r and mass m rolls without slipping on a smooth horizontal surface. A constant force of magnitude P is applied to the rim of the disk at distance r above the horizontal surface and in the direction of motion. r,m,P are known. what is the angular acceleration in terms of known quantities, and what force P will cause the disk to begin slipping if the coefficient of static friction is u between disk and horizontal surface? what distance d will the disk's center of mass have traveled when it reaches a speed v?

mechanics - rod/pin apparatus

Rigid rod OA is 2 ft long and rotated around fixed pt O. This rod is pinned at A to rigid connecting rod AB, 6 ft long, which in turn is pinned at B to piston C. This piston moves without friction along the y axis. The pins are also frictionless. Rod OA is positioned so that it is pi/3 radians above the x-axis and angular velocity = 2 rad/sec counterclockwise and its angular acceleration is 0. What are the velocity and acceleration of the piston in this case? and... Weights of the three components are as follows: W(OA)=64.4 lb, W(AB) = 16.1 lb, W(C) = 5 lb. A constant counterclockwise torque is applied to rod OA at O. The system starts from rest with rod OA horizontal to the right. Wha... click for more

Understanding a collision of 2 blocks and its forces and energies.

How do you determine the speed just before blocks collide? How do you determine the temperature rise that results from the collision? How do you determine the additional thermal energy that is generated as the blocks continue to move together after the collision?

Understanding moments of a system with trestles.

How can I calculate the moments on a system with trestles?

Given initial velocities of two particles, what are their velocities after they collide?

Two particles, of mass 1 kg and 3 kg, are traveling towards each other with velocities of 100 m/s and -40 m/s respectively. Using the laws of physics (e.g. conservation of energy & momentum) calculate the following: a) What are the initial energies of the particles? b) What are the final velocities of the particles? c) Which particle gained energy, and which lost energy?