A 0.75 kg fish looking to strike at its prey accelerates from rest to 2 m/s in 0.25 second. If the average drag force from the water is 1.50 N, what is the forward force on the fish (that is the thrust that the tail fin makes when it pushes on the water)?

7.5 N

Explanation:

Given that a 0.75 kg fish looking to strike at its prey accelerates from rest to 2 m/s in 0.25 second. If the average drag force from the water is 1.50 N, what is the forward force on the fish (that is the thrust that the tail fin makes when it pushes on the water)?

Solution.

Since it accelerates from rest, initial velocity will be equal to zero.

Acceleration = velocity/time

Acceleration = 2 / 0.25

Acceleration = 8 m/s

Net force = mass × acceleration

F - 1.5 = 0.75 × 8

Where F = forward force of the fish.

F - 1.5 = 6

F = 6 + 1.5

F = 7.5N

Therefore, the force force on the fish is 7.5N.