A barge is pushed through the water by 2 tugboats as shown in the diagram below.

Question

A barge is pushed through the water by 2 tugboats as shown in the diagram below. The mass of the barge and its contents is 4800 tonnes and its acceleration in the water is 

8.30 cm/s2. Determine the drag force of the water on the barge resisting the motion. Assume that the drag force acts in the direction opposite to the motion of the barge.  

f1=364000 N [s]

f2=448000 N [W]

Diagram can't be shown.

 

Answer 1

Since the forces f₁ and f₂ are perpendicular, the resultant is found using the pythagorean theorem.

R=√(f₁² + f₂²) =√(364000²+448000²)=560000N

Take note that 1 tonne=1000kg and 1cm=10^-2m

Now the drag force acts opposite this force so R-drag= ma =4800000(8.30X10^-2)=398400N

Thus drag force = R-398400=560000-398400=161600N