Question

In the figure, a ball is thrown leftward from the left edge of the roof, at height habove the ground. The ball hits the ground 2.10 s later, at distance d - 30.0 m from the building and at angle 8 - 64.0° with the horizontal. (a) Find h. (Hint: One way is to reverse the motion, as if on videotape.) What are the (b) magnitude and (c) angle relative to the horizontal of the velocity at which the ball is thrown (positive angle for above horizontal, negative for below)? (a) Number Units (b) Number Units (c) Number Units

Answer 1

Page Assume initial relocity Tusime UR U cose mis relocity along xanis Ux = U case relocity along y-aseis uy = using acceleration along x - asis an = 0 acceleration alon long yosis ay=-g if final relocity is v ac ll vec Usino to Jo 2X21 vcoso along X direction Ax no u cos e = veosa ....i add assume tet time taken at ; for o aris : Sx = Usttt ant? d ucoso t + / XOXL2 d ucos +(14.2012 t = d ucos

u oso ad square egn (ii) & eu, and add uksine tuleoso = (-8.71) ²4 (14.2017 14.28. t :. tesimo y coso - 14.28 14.28 14.28 cos 64° V = 32.59.mis -Vsim ' final relocity is 32.59 m/s Now for y-anis Vy = Uy tayt Usino – 9.8X8.1 - 32.597 Sim 640 Usimo - 928 X24 -29.29 + 20-58 Usino usind -8.71 ... (ii) ucoso --cing 14.28 Uelsino + cos²0) = 226.6625 42 = 226-6625 u=15.06 mis Orchies

Page.. 15.06 mls initial relocity usim = 8.71 sinor -8.71 = -8.71 15.06 -35.380 Now who byt - 1 x 9.8 t2 -h= -8.71 X 2.10 - 1x 9.8 XR.132 h = 39.9m (a) (b) (C) h=39.gm U= 15.06mls - 35:33° 200