Calculating Cannon Ball Time to Hit Ground in Physics Problem
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Solve a physics problem where two cannon balls are launched and calculate which one hits the ground first using equations of motion. Find the impact time and distance traveled for each.
Calculating Cannon Ball Time to Hit Ground in Physics Problem
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ConcepTest 6 Followup • 0 = -0.5*9.8t2 + Voyt, • 4.9t2 - V0sin(q)t = 0. • t{4.9t - V0sin(q)}= 0. Thus, t = 0 or t = V0sin(q)/4.9 Which cannon ball hits the ground first? Cannon Ball A Cannon Ball B Both cannon balls hit the ground at the same time. B A Marker
y Example Problem #3.21 v0x = v0cos600 = 3.2 m/s v0y = v0sin600 = 5.54 m/s v0 = 6.4 m/s y = ? 600 x x = 2.1 m • (a) Basically means, “Find value of y when x = 2.1 m.” • Find time when x = 2.1 m: x = 2.1 m = x0 + v0xt = 0 + v0xt t = 2.1 m / 3.2 m/s t = 0.656 s • Now substitute this into equation for y: y = y0 + voyt – 0.5gt2 y = 0 + (5.54 m/s)(0.656 s) – 0.5(9.8 m/s2)(0.656 s)2 = 1.53 m (b) vy = v0y – gt = 5.54 m/s – (9.8 m/s2)(0.656 s) = –0.89 m/s
N F = 80 N W Example Problem #4.10 Free-body diagram: y x (a) S Fx = max S Fy = may = 0 (no motion in y – direction) F = max N – W = 0 N = W All acceleration is in the x – direction , so use atotal = ax = 2(x – x0) / t2.