The masses of blocks ?A? and ?B? in Fig are 20.0 kg and 10.0 kg, respectively. The blocks are initially at rest on the floor and are connected by a massless string passing over a massless and frictionless pulley. An upward force is applied to the pulley. Find the accelerations of block ?A? and of block ? ? when F? is (a) 124 N; (b) 294 N; (c) 424 N. Figure:

Leslie Ogu CSCI 4531 09/06/2016 Chapter 2: Encryption Symmetric Encryption + The universal technique for providing confidentiality for transmitted or stored data + Also referred to as conventional encryption or singlekey encryption + Two requirements to use: + Need a strong encryption algorithm + Sender and receiver must have obtained copies of the secret key in a secure fashion and and must keep the key secure + Only alternative before publickey encryption in 1970’s + Still most widely used alternative + 5 Ingredients + Plaintext + Encryption algorithm + Secret key + Ciphertext