SARET CRKS AUTOWAY 12. A stone is dropped from the top of a cliff. It is seen to hit the ground below after 3.55 s. How high is the cliff? 13. A ball is dropped from rest at the top of a building that is 320 m tall. Assuming no air resistance, what is the speed of the ball just before it strikes the ground? 14. Estimate (a) how long it took King Kong to fall straight down from the top of the Empire State Building (280m high), and (b) his velocity just before "landing". Useful equations For Constant Velocity: V => D X = V₁t + Xo For Constant Acceleration: Vr = V + at X = Xo+Vot + v=V+2a(X-Xo) \prom = V +V V velocity t = time D Distance X = Final Position Xo Initial Position V = Final Velocity Vo Initial Velocity a = acceleration For free fall Yf = Final Position Yo Initial Position g = 9.80 m $2 For free fall: V = V + gt Y=Yo+Vo t + +gt V,² = V₁²+2g (Y-Yo) V+Vo Vprom= 2 6

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A 11 kg weight is attached to a spring with constant k = 99 N/m and subjected to an external force F(t) =-704 sin(5t). The weight is initially displaced 4 meters above equilibrium and given an upward velocity of 5 m/s. Find its displacement for t> 0. y(t) ון