- Length of the plate (L) = 2 m
- Width of the plate (W) = 1.5 m
- Speed of towing (V) = 30 km/h
- Drag coefficient (Cd) = 0.20
- Lift coefficient (Cl) = 0.60


The resultant force on the plate can be divided into two components: the drag force (Fd) and the lift force (Fl).

1. The drag force (Fd) can be calculated using the drag coefficient (Cd) and the dynamic pressure (q). The dynamic pressure (q) can be calculated using the formula:

q = 0.5 * ρ * V^2

where ρ is the density of water (assumed to be 1000 kg/m^3) and V is the velocity of towing in m/s.

After calculating the dynamic pressure (q), the drag force (Fd) can be calculated using the formula:

Fd = Cd * q * A

where A is the area of the plate, which is given by:

A = L * W

2. The lift force (Fl) can be calculated using the lift coefficient (Cl) and the dynamic pressure (q). The lift force (Fl) can be calculated using the formula:

Fl = Cl * q * A

3. The resultant force (Fr) can be calculated by taking the square root of the sum of the squares of the drag force (Fd) and the lift force (Fl):

Fr = √(Fd^2 + Fl^2)


The power required to keep the plate in motion can be calculated using the formula:

P = Fr * V

where P is the power in watts, Fr is the resultant force in newtons, and V is the velocity of towing in m/s.

To convert the power from watts to kilowatts, divide the power by 1000.


Using the given information, we can calculate the resultant force (Fr) and the power required (P) as follows:

- Velocity of towing (V) = 30 km/h = 30 * 1000 / 3600 = 8.33 m/s
- Dynamic pressure (q) = 0.5 * 1000 * (8.33)^2 = 34,721.81 Pa
- Area of the plate (A) = 2 * 1.5 = 3 m^2
- Drag force (Fd) = 0.20 * 34,721.81 * 3 = 20,833.09 N
- Lift force (Fl) = 0.60 * 34,721.81 * 3 = 62,499.27 N
- Resultant force (Fr) = √(20,833.09^2 + 62,499.27^2) = 66,019.86 N
- Power required (P) = 66,019.86 * 8.33 = 550,150.02 W = 550.15 kW


The resultant force on the plate is approximately 66,019.86