Answer:
a) t = 1.75 s
b) x = 31.5 m
Step-by-step explanation:
a) The time at which Tom should drop the net can be found using the following equation:
![y_(f) = y_(0) + v_(oy)t - (1)/(2)gt^(2)](https://img.qammunity.org/2021/formulas/physics/college/pibot5f6laf2u1h503xf7n3httm0gummx7.png)
Where:
: is the final height = 0
y₀: is the initial height = 15 m
g: is the gravity = 9.81 m/s²
: is the initial vertical velocity of the net = 0 (it is dropped from rest)
![0 = 15m - (1)/(2)9.81 m/s^(2)*t^(2)](https://img.qammunity.org/2021/formulas/physics/college/332h7vdqnudsoackisg2ywvysd5g8c8sfp.png)
![t = \sqrt{(2*15 m)/(9.81 m/s^(2))} = 1.75 s](https://img.qammunity.org/2021/formulas/physics/college/91dpv1s2q65hoj4vj44hves26iyrqfcg0i.png)
Hence, Tom should drop the net at 1.75 s before Jerry is under the bridge.
b) We can find the distance at which is Jerry when Tom drops the net as follows:
![v = (x)/(t)](https://img.qammunity.org/2021/formulas/physics/high-school/l2p658hq6gefmtsqzd7sjx859lzq85dvan.png)
![x = v*t = 18 m/s*1.75 m = 31.5 m](https://img.qammunity.org/2021/formulas/physics/college/m9xd1aw581p4adk04i4nhijg3pqi6qf0zs.png)
Then, Jerry is at 31.5 meters from the bridge when Jerry drops the net.
I hope it helps you!