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A rock is thrown off a 100.0m cliff upward at an angle of 20o to the horizontal. It has an initial velocity of 15ms-1 and strikes the rocks below.
Find how far away the rock is from the base of the cliff.
I calculated total time of flight (projectile parabola + 100m vertical descent) which equalled around 4.3-5.0 (verified by textbook.)
The total time of flight for the parabolic section was about 1.046s
Horizontal component = 15cos20 = 14.095ms-1
SH = ut = 14.095 x 1.046 = 14.74m.
However, the answer is 70m and you can only acquire that by 14.095 x 5 which doesn't make sense because I thought after being projected at an angle it would make a completely vertical descent thus having no effect whatsoever on the horizontal component.
Find how far away the rock is from the base of the cliff.
I calculated total time of flight (projectile parabola + 100m vertical descent) which equalled around 4.3-5.0 (verified by textbook.)
The total time of flight for the parabolic section was about 1.046s
Horizontal component = 15cos20 = 14.095ms-1
SH = ut = 14.095 x 1.046 = 14.74m.
However, the answer is 70m and you can only acquire that by 14.095 x 5 which doesn't make sense because I thought after being projected at an angle it would make a completely vertical descent thus having no effect whatsoever on the horizontal component.