Question

The tension at which a fishing line snaps is commonly called the line's "strength." What minimum strength is needed for a line that is to stop a salmon of weight 85 N in 11.0 cm if the fish is initially drifting at 2.8 m/s? Assume a constant deceleration.

Answer 1

At initial velocity u=2.8 m/s the fish is stopped in a distance of S=0.11m. The acceleration a is therefore:
2aS = u²-0²
Solve for a (negative).

Use F=ma to find the required strength.
In practice, you would double that value to give a factor of safety of 2 if you don't want the big fish to go away.

Answer 2

tension= mass*acceleartion=85/g *a

now, to find a.
Vf^2=Vi^2+2ad
0=2.8^2+2a*.11
solve for a.

Answer 3

-3.40 x 10^1 N