Answer:
![t = (1)/(4)\sqrt d](https://img.qammunity.org/2022/formulas/mathematics/college/5tqtu3ae2dgjy30ismkmu7oqx2x2dsa8gj.png)
Time to reach 100ft is 2.5 seconds
Explanation:
Given
![d = 16t^2](https://img.qammunity.org/2022/formulas/mathematics/college/ldxrhz481zptd30d92w03kranmjo8ohe3z.png)
Solving (a): Determine the inverse function
![d = 16t^2](https://img.qammunity.org/2022/formulas/mathematics/college/ldxrhz481zptd30d92w03kranmjo8ohe3z.png)
Swap the positions of d and t
![t = 16d^2](https://img.qammunity.org/2022/formulas/mathematics/college/q1reu0bptjb3sdmr8bm2e1h6hy1mc9ko7t.png)
Make d the subject
![(t)/(16) = d^2](https://img.qammunity.org/2022/formulas/mathematics/college/uwjzh6ec9feoumuhky6ct155s6odmfgcnc.png)
Take positive square root of both sides
![\sqrt{(t)/(16)} = d](https://img.qammunity.org/2022/formulas/mathematics/college/elyyncqhxc180o34eqj2a0u5pkhezru8rw.png)
![d = \sqrt{(t)/(16)}](https://img.qammunity.org/2022/formulas/mathematics/college/l46olm28vqmzgkkrop2bgd37r45lxspw32.png)
![d = (1)/(4)\sqrt t](https://img.qammunity.org/2022/formulas/mathematics/college/1e3hsmfi5v20x9yw52cto8a3gsi38moo1j.png)
Swap the positions of d and t
--- The inverse function
Solving (b): Find t when d =100
Substitute 100 for d in
![t = (1)/(4)\sqrt d](https://img.qammunity.org/2022/formulas/mathematics/college/5tqtu3ae2dgjy30ismkmu7oqx2x2dsa8gj.png)
![t = (1)/(4)\sqrt {100](https://img.qammunity.org/2022/formulas/mathematics/college/27wtd2h2ccj9up1arxpoiqo91ke0yng29w.png)
![t = (1)/(4)* 10](https://img.qammunity.org/2022/formulas/mathematics/college/rrur2qer658jcpohce000me9jd4pu51g4j.png)
![t = (1* 10)/(4)](https://img.qammunity.org/2022/formulas/mathematics/college/blmtqa5vbmg425w1e3jb3814wrssn7j3u1.png)
![t = (10)/(4)](https://img.qammunity.org/2022/formulas/mathematics/college/gv0zlmkl80xjbr7qd0jj3ordkwhguhcanp.png)
![t = 2.5](https://img.qammunity.org/2022/formulas/mathematics/college/nfadvaurjbnbsmjh3vecj9v26owgrd378o.png)