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1. a steak knife is made up of which simple machines?

a. lever and pulley
b. wedge and screw
c. pulley and a screw
d. lever and wedge

2. a pair of scissors is made up of what simple machines?

a. wedge and screw
b. lever and pulley
c. lever and wedge
d. screw and pulley

3.the knee is an example of a simple machine in the human body.

true
false

Consider the following statements: #include #include class temporary { private: string description; double first; double second; public: temporary(string = "", double = 0.0, double = 0.0); void set(string, double, double); double manipulate(); void get(string& , double& , double& ); void setdescription(string); void setfirst(double); void setsecond(double); }; write the definition of the member function set() so that the instance variables are set according to the parameters. write the definition of the constructor so that it initializes the instance variables using the function set() write the definition of the member function manipulate() that returns a decimal number (double) as follows: if the value of description is "rectangle", it returns first * second if the value of description is "circle" it returns the area of a circle with radius first if the value of description is "cylinder" it returns the volume of a cylinder with radius first and height second. hint: the volume of a cylinder is simply the area of the circle at the base times the height. if the value of description is "sphere" it returns the volume of the sphere with radius first. otherwise it returns -1.0;

Consider a slotted aloha system, where the time slot equals the fixed duration of each packet. assume that there are 4 stations a,b,c,d sharing the medium. (a) stations a,b,c,d receive one packet each from higher layers at times 1.3, 1.5, 2.6,5.7 respectively. show which transmissions take place when, according to the slottedaloha protocol; describe all transmissions until all four packets have been successful.when needed, each station has access to the following sequence of random number, provided by a random number generator and drawn uniformly between 0 and 1: (1) station a draws numbers: 0.31, 0.27, 0.78, 0.9, 0.9, 0.11, 0. (2) station b draws numbers: 0.45, 0.28, 0.11, 0.83, 0.37, 0.22, 0. (3)station c draws numbers: 0.1, 0.2, 0.3, 0.4, 0. (4) station d draws numbers: 0.36, 0.77, 0.9, 0.1, 0.1, 0.1, 0.1, 0. (b) in slotted aloha, a station transmits in each time slot with a given probability. what probabilities would you assign to each of the four stations so as to: (i) maximize the efficiency of the protocol? (ii) maximize fairness among the four stations? (c) will the efficiency increase or decrease if we modify slotted aloha as follows: (i) get rid of slots and allow stations to transmit immediately? (ii) implement carrier sensing? (iii) implement collision detection? (iv) implement collision avoidance?

Knowing that the central portion of link bd has a uniform cross sectional area of 800 mm2 , determine the magnitude of the load p for which the normal stress in link bd is 50 mpa. (hint: link bd is a two-force member.) ans: p = 62.7 kn