Question

A discus is thrown from a height of 4 feet with an initial velocity of 65 ft/s at an angle of 44° with the horizontal. How long will it take for the discus to reach the ground?
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Answer 1

Answer:

The total time it will take for the discus to reach the ground is 2.892 s

Step-by-step explanation:

To answer the question, we will first calculate the total time before the discus touches the ground as follows;

The vertical component of the velocity = v × sinθ =  65 × sin 44° = 45.153 ft/s

Maximum height reached = v² = u² - 2 × g × h

0² = 45.153² - 2×32.2×h

h = 45.153²/(2×32.2) = 31.673 ft

Time to reach maximum height is v = u - gt, t = u/g. where v = 0

t = 45.153/32.2 = 1.403 s

Time to go from maximum height to just before touching the ground is given by s = u·t + 0.5·g·t², which gives;

31.673 + 4 = 0×t + 0.5×32.2×t²

2.21673 = t²

t = 1.49 s

Therefore the total time of the discus flight = 1.403 + 1.49 = 2.892 s

Which means, the total time it will take for the discus to reach the ground = 2.892 s.