By Clifford Newton. Mills

ISBN-10: 1152039687

ISBN-13: 9781152039681

Writer: ny, D. Van Nostrand corporation book date: 1916 topics: Mechanics Notes: this can be an OCR reprint. there's typos or lacking textual content. There aren't any illustrations or indexes. should you purchase the overall Books version of this publication you get loose trial entry to Million-Books.com the place you could choose from greater than one million books at no cost. it's also possible to preview the booklet there.

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Additional resources for A Short Course in Elementary Mechanics for Engineers

Sample text

Lbs. 32 Total K. E. before impact Total K. E. -lbs. E. -lbs. EXAMPLES X 1. The hammer of a pile driver weighs Its potential energy when it has been i ton. Find lifted 10 feet. A body of weight 320 pounds is thrown up verwith a velocity of 32 feet per second. What is kinetic energy (i) after half a second, and (2) after 2. tically its one second? 3. 62 tons is hour, and is pounds each 4. in weight? A ball weighing 5 of 1000 ing the kinetic energy of a street car weighing it is moving at a speed of 7 J miles per laden with 20 passengers averaging 150 when it ounces, and moving with a velocity and after pierc- feet per second, strikes a shield, moves on with a velocity of 400 feet per second.

Then the change in velocity (2^2—^1) —{v2-n)= g =0^1* is constant, Hence — .... at (53) g But — a = forceF, (54) g therefore — (zJ2— ^1)= force which means that the change in to the impulse. X time, . momentum . (55) is equal W Example i. A car weighing pounds is set in motion by a uniform force of Pi pounds and in h seconds it attains a velocity of V feet per second. A in retarding force of P2 pounds brings the car to rest Find the relation between Pi, P2, t2 seconds. andF. During the time h the gain Solution, mentum is WV — g in mo- .

Work. and (b) is If the required? Energy is defined as the capacity for doing There are two kinds of energy, called potential kinetic. E. =|-z;2 (66) g Hence is it equal to the proven that the work done easily change that of kinetic energy; K. E. ^i-(v2^-vi^)^FXs, . (67) g It is evident that the consideration of often be solved problems which are solved from changes of momentum, might by considering the change of kinetic energy. A weight of 3 tons has been lifted i. of 8 feet. What is the potential a distance vertically energy which the weight possesses at this height?