A brick is released at rest from the roof of a building and strikes the ground

# A brick is released at rest from the roof of a

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14. A brick is released at rest from the roof of a building and strikes the ground in 3s, encountering no appreciable air drag. (3 points) (a) How tall is the building? ___________________________ (b) How fast is the brick moving just before it reaches the ground? _________________
Name (print): TYPE: A(Last) (First) 615. See Figure below regarding the movement of three persons. Person A moves with constant velocity from A0at t0=0 s to A1 at t1= 2 s, meanwhile Person B moves with constant velocity from B0 to B1during the same time interval. Person C stays at the origin and does not move. (Unit is required. Total 3 points.) (a) From point view of Person C (that is, C is the observer/reference) (a1) x and y components of person A’s position at time t1 = _________and _________. (b) From point view of Person B (that is, B is the observer/reference) (b1) x and y components of person C’s position at time t1= ________ and _________. (b2) x and y components of person A’s velocity between t0 and t=___________and __________. 1 -2m -2m -9m
Name (print): TYPE: A(Last) (First) 10Possibly useful Formula Sheet DisplacementΔr = r2-r1 Average velocityAverage accelerationg=9.8 m/s2Constant acceleration in x Constant acceleration in y vx=v0x+axt vy=v0y+ayt x=x0+v0x t+axt2/2 y=y0+v0y t+ayt2/2 vx2=v0x2+2ax(x-x0) vy2=v0y2+2ay(y-y0) Projectile motion vx=v0xx=x0+v0x t vy=v0y+ayt y=y0+v0y t+ayt2/2 vy2=v0y2+2ay(y-y0) A right triangle: a2+b2=c2 Conversion factors: 1 m = 39.37 inches, 1 km = 1000 m, 1 mile = 1.609 km, 1 kg = 2.20 lb. Relative velocity. VA|B= VA|C+VC|B VA|B= - VB|AUniform circular motion. a = v2/R
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