The rock's height <em>y</em> at time <em>t</em> is given by
<em>y</em> = 45 m + (7.2 m/s) <em>t</em> - 1/2 <em>g</em> <em>t </em>²
where <em>g</em> = 9.80 m/s² is the magnitude of the acceleration due to gravity. Set <em>y</em> = 0 and solve for <em>t</em> :
0 = 45 m + (7.2 m/s) <em>t</em> - 1/2 <em>g</em> <em>t </em>² → <em>t</em> ≈ 3.9 s
Explanation:
because his lower body is in inertia of motion.
Hope it helps
<span>Flow rate through pipe a is 0.4 m3/s
Parallel pipes have a diameter D = 30 cm => r = 15 cm = 0.15 m
Length of Pipe a = 1000m
Length of Pipe b = 2650m
Temparature = 15 degrees
Va = V / A = (0.4m3/s) / (3.14 (0.15m)^2) = 5.66 m/s
h = (f(LV^2)) / D2g
(fa(LaVa^2)) / Da2g = (fb(LbVb^2)) / Da2g and Da = Db; fa = fb
LaVa^2 = LbVb^2 => La/Lb = Vb^2/Va^2
Vd^2 = Va^2(La/Lb) => Vb = Va(La/Lb)^(1/2)
Vb = 5.66 (1000/2650)^(1/2) => 5.66 x 0.6143 = 3.4769 m/s
Vb = 3.4769 m/s
V = AVb = 3.14(0.15)^2 x 3.4769 m/s = 0.245 m^3/s</span>
By balancing the force, we get :
100 - Frictional Force = ma
100 - μmg = ma
100 - μ(5)(10) = (5)(15)
50μ = 25
μ = 0.5
Distance travelled by box in 5 seconds is :
Hence, this is the required solution.