Question

ment #1 배 Files s/1497269/files?preview 60718168 Page < of 4 5. A projectile is fired from point 0 at the edge of a cliff, with initial velocity components of ox 60 m's and 175 m/s, as shown in the figure. The projectile rises and then falls into the sea at point P. The time of flight of the projectile is 40.0 s, and it experiences no air resistance in flight. Find (a) Initial velocity of the projectile, (b) Launch angle, (c) Magnitude of the velocity of projectile when it hits water? (d) Distance D, (e) Maximum height reached by the projectile above the sea level, (f) Height of the cliff

Answer 1

a)

u^2 = 60^2 + 175^2

u = 185 m/s

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b)

x = arctan ( Voy / Vox) = 71.08

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c)

height of the cliff

h = ho + Voy * t - 0.5* gt^2

0 = ho + 175*40 - 0.5* 9.8* 40^2

ho = 840 m

using energy conservation

0.5 m u^2 + mgho = 0.5 m v^2

0.5* 185^2 + 9.8* 840 = 0.5* v^2

v = 225.142 m/s

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d)

D = Vox * t = 60* 40 = 2400 m

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e)

hm = ho + voy^2/ (2 g)

hm = 840 + 175^2 / ( 2*9.8)

hm = 2402.5 m

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f)

ho = 840 m

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