1. Identify the Forces:

* Weight (Fg): The force of gravity acting on the pail, calculated as Fg = mass * acceleration due to gravity (g). So, Fg = 20 kg * 9.8 m/s² = 196 N.

* Applied Force (Fa): The force pulling the pail upward, which is 400 N.

2. Determine the Net Force:

* Net Force (Fnet): The difference between the applied force and the weight. Since the applied force is upward and the weight is downward, we subtract: Fnet = Fa - Fg = 400 N - 196 N = 204 N.

3. Calculate the Acceleration:

* Acceleration (a): Use Newton's Second Law of Motion: Fnet = mass * acceleration (a). Rearrange to solve for acceleration: a = Fnet / mass.

* Substitute values: a = 204 N / 20 kg = 10.2 m/s².

Therefore, the acceleration of the pail of cement is 10.2 m/s² upwards.