Need help on Physics!! MOTION IN TWO AND THREE DIMENSIONS?
2015-09-30 8:34 am
A stone is projected at a cliff of height h with an initial speed of 42.0 m/s directed at angle α = 60.0˚ above the horizontal.The stone strikes at A. 5.50 s after launching. Find (a) the height h of the cliff, (b) the speed of the stone just before impact at A. and (e) the maximum height H reached above the ground.
回答 (1)
2015-09-30 9:22 am
✔ 最佳答案
-h = 42sin Θ*t-4.903t^2-h = 42*0.866*5.50-4.903*5.5^2 = -51.730
h = 51.730 m
Δh = (42*0.866)^2/19.612 = 67.45 m
H = h+Δh = 51.730+67.45 = 119.18 m
Vf = √V^2+2gh = √42^2+19.612*51.73 = 52.71 m/sec
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