Step-by-step explanation:
It is given that,
Mass of bullet, m₁ = 0.0207 kg
Mass of wooden block, m₂ = 28 kg
Wooden block is initially at rest, u₂ = 0 m/s
After the collision the, system has speed of, v = 1.180 m/s
We need to find the initial speed (u₁) of the bullet. It can be calculated using the conservation of linear momentum as :
![m_1u_1+m_2u_2=(m_1+m_2)v](https://img.qammunity.org/2020/formulas/physics/middle-school/sqrbqbcjlah6n2s4i5v2clcyygsk5uk63q.png)
![0.0207\ kg* u_1+0=(0.0207\ kg+28\ kg)* 1.180\ m/s](https://img.qammunity.org/2020/formulas/physics/college/uy7ufm905we9r3iplu9e4gwy4kha8bcpyy.png)
![0.0207* u_1=33.06](https://img.qammunity.org/2020/formulas/physics/college/kg1eq0yf48e81nlwazu1lz7tjd78m6ct63.png)
![u_1=1597.10\ m/s](https://img.qammunity.org/2020/formulas/physics/college/ezdw89tbm5s6xkkqxfvk1he9i6gm6wckl1.png)
So, the initial speed of the bullet is 1597.10 m/s. Hence, this is the required solution.