A 46.0-kg projectile is fired atan angle of 30.0° above the horizontal with an i

Question

A 46.0-kg projectile is fired atan angle of 30.0° above the horizontal with an initial speedof 134 m/s from the top of acliff 154 m above levelground, where the ground is taken to be y = 0. (a) What is the initial total mechanical energy of theprojectile?
J

(b) Suppose the projectile is traveling 85.0 m/s at its maximumheight of y = 356 m. How much work has been done on theprojectile by air friction?
J

(c) What is the speed of the projectile immediately before it hitsthe ground if air friction does one and a half times as much workon the projectile when it is going down as it did when it was goingup?
m/s
(a) What is the initial total mechanical energy of theprojectile?
J

(b) Suppose the projectile is traveling 85.0 m/s at its maximumheight of y = 356 m. How much work has been done on theprojectile by air friction?
J

(c) What is the speed of the projectile immediately before it hitsthe ground if air friction does one and a half times as much workon the projectile when it is going down as it did when it was goingup?
m/s

Explanation / Answer

For part a use: 1/2mv2+mgh =1/2(46)(1342)+46(9.8)(154) =482411J For part b use: v2-u2=2gs u2=2(9.8)(202)=62.9 852+62.92=105.7 then use1/2m(v12-v22) 1/2(46)(1342-105.72)=156021J Sorry but I don't know how to do part c!

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