Physics urgent help plz.

• Mar 1st 2008, 03:47 AM
MonkiezDevil
Physics urgent help plz.
Problem:
A fisherman yanks a fish out of the water with a=4.5 m/s^2 using a light fishing line (neglect the weight of the fishing line) which has a test value of 22N: The line snaps -- What can you say about the weight of the fish?

Answer: The mass of the fish is more than 1.5kg

Can anyone show me how to work this question out?

Thank you very much.
• Mar 1st 2008, 04:04 AM
mr fantastic
Quote:

Originally Posted by MonkiezDevil
Problem:
A fisherman yanks a fish out of the water with a=4.5 m/s^2 using a light fishing line (neglect the weight of the fishing line) which has a test value of 22N: The line snaps -- What can you say about the weight of the fish?

Answer: The mass of the fish is more than 1.5kg

Can anyone show me how to work this question out?

Thank you very much.

Net force = T - mg where T is the tension in the line, m is the mass of the fish and g = 9.8 is the acceleration due to gravity.

But net force = ma = m(4.5).

Therefore 4.5 m = T - 9.8m => 14.3 m = T.

The maximum value of T is 22N. If the line snaps, then T > 22N.

Therefore 14.3 m > 22 => m > 22/14.3 = 1.5 (correct to 1 decimal place).