In this problem, we are already given the equation for height h in terms of time t. So, the only thing you would do is substitute h and solve for t. If the height is given as 1.414 m, then the solution would be:
h=−4.9t² <span>+ 9.1t +1.4
1.414 = </span>−4.9t² + 9.1t +1.4
−4.9t² + 9.1t - 0.014 = 0
Since this is a quadratic equation, there can be two answer for this equation. They are t = 1.859 seconds, -0.001537 seconds. Since the negative answer is impossible, the answer would be 1.859 seconds.
Answer:
a
Explanation:
the other answers wouldnt help
Answer:
a) 30.82 m/s
b) 183.33 Hz
Explanation:
a)
V = speed of the sound = 339 m/s
v = speed of the train = ?
f' = observed frequency by the observer = 220 Hz
f = actual frequency of the observer = 200 Hz
using the equation


v = 30.82 m/s
b)
V = speed of the sound = 339 m/s
v = speed of the train = 30.82 m/s
f'' = observed frequency by the observer as train moves away = ?
f = actual frequency of the observer = 200 Hz
using the equation


f'' = 183.33 Hz