Answer:
The equation for the height of the penny in function of time is:
![h(t)=1451-16t^2](https://tex.z-dn.net/?f=h%28t%29%3D1451-16t%5E2)
After 7 seconds, the penny will be at a height of 667 feet.
Step-by-step explanation:
The penny will have a free fall.
The initial velocity is zero, and the initial height is h(0)=1,451.
The acceleration will be the gravity, that has a value g=32 ft/s^2.
Then, we can model this starting by the speed:
![dv/dt=-g\\\\v(t)=v_0-gt=-gt](https://tex.z-dn.net/?f=dv%2Fdt%3D-g%5C%5C%5C%5Cv%28t%29%3Dv_0-gt%3D-gt)
Then, the height becomes:
![dh/dt=v(t)=-gt\\\\h(t)=h_0-\dfrac{gt^2}{2}=1451-\dfrac{32}{2}t^2\\\\\\h(t)=1451-16t^2](https://tex.z-dn.net/?f=dh%2Fdt%3Dv%28t%29%3D-gt%5C%5C%5C%5Ch%28t%29%3Dh_0-%5Cdfrac%7Bgt%5E2%7D%7B2%7D%3D1451-%5Cdfrac%7B32%7D%7B2%7Dt%5E2%5C%5C%5C%5C%5C%5Ch%28t%29%3D1451-16t%5E2)
The approximate height of the penny after 7 seconds can be calculated as:
![h(7)=1451-16(7^2)=1451-16*49=1451-784=667](https://tex.z-dn.net/?f=h%287%29%3D1451-16%287%5E2%29%3D1451-16%2A49%3D1451-784%3D667)
After 7 seconds, the penny will be at a height of 667 feet.