Introduction:
The Bob of a pendulum is released from a horizontal position A and swings down to the lowermost point B. We need to determine the speed at which the Bob arrives at point B, considering that it dissipates 5% of its initial energy against air resistance.

Understanding the Problem:
To solve this problem, we need to consider the conservation of mechanical energy. The mechanical energy of the system is given by the sum of the kinetic energy and potential energy. At point A, the pendulum is at its highest position, so it has maximum potential energy and zero kinetic energy. At point B, the pendulum is at its lowest position, so it has maximum kinetic energy and zero potential energy.

Conservation of Mechanical Energy:
The conservation of mechanical energy states that the total mechanical energy of a system remains constant if no external forces, such as friction, are acting on it. In this case, we need to account for the energy dissipated due to air resistance.

Calculating the Initial Energy:
To calculate the initial energy, we need to determine the potential energy of the pendulum at point A. The potential energy is given by the formula PE = mgh, where m is the mass of the Bob, g is the acceleration due to gravity, and h is the height of the pendulum. In this case, the height h is equal to the length of the pendulum, which is 1.5m.

Calculating the Energy Dissipated:
Given that the pendulum dissipates 5% of its initial energy against air resistance, we can calculate the energy dissipated by multiplying the initial energy by 0.05.

Calculating the Final Energy:
The final energy of the system is equal to the initial energy minus the energy dissipated. This gives us the energy available for the Bob at point B.

Calculating the Speed:
The final energy of the system is equal to the kinetic energy at point B. The kinetic energy is given by the formula KE = 0.5mv^2, where m is the mass of the Bob and v is its velocity. By rearranging the equation, we can solve for v.

Conclusion:
By applying the conservation of mechanical energy and accounting for the energy dissipated due to air resistance, we can determine the speed at which the Bob arrives at the lowermost point B. The initial energy is calculated using the potential energy formula, and the energy dissipated is found by multiplying the initial energy by 0.05. The final energy is obtained by subtracting the energy dissipated from the initial energy. Finally, we can calculate the speed at point B by using the kinetic energy formula and solving for velocity.