An airplane is flying with a velocity of 234 m/s at an angle of 30.0° with the horizontal, as the drawing shows. When the altitude of the plane is 2.7 km, a flare is released from the plane. The flare hits the target on the ground.
Keep getting 50.3 and I don't know what I'm doing wrong!
What is the angle θ?
回答 (1)
2018-01-23 5:34 pm
✔ 最佳答案
Consider the vertical direction :Take g = 9.81 m/s²
Take all downward quantities to be positive.
Initial speed, u(y) = 234 sin30.0° m/s
Displacement, s(y) = 2.7 km = 2700 m
Acceleration, a(y) = 9.81 m/s²
s(y) = u(y) t + (1/2) a(y) t²
2700 = (234 sin30.0°)t + (1/2)(9.81)t²
9.81t² + 234t - 5400 = 0
t = 14.4 s or t = -38.2 s (rejected)
Horizontal distance = (234 cos30.0°) (14.4) = 2920 m
tanθ = 2700/2920
Then, θ = tan⁻¹(2700/2920) = 42.8°
收錄日期: 2021-04-24 00:55:04
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20180123061306AAuDV51