1. A boat starts from rest and travels 5250m in 2.20 minutes. It has a mass of 3460 kg. What is the net force exerted? 2. A truck exerts a force of 2400N for 36 seconds and has a mass of 35000 kg. If it starts from rest, what is it’s final velocity?

2085.06N

2.47m/s

Explanation:

Question 1

Given parameters:

Mass of boat = 3460kg

Distance traveled by boat = 5250m

Time taken for travel = 2.20minutes.

Unknown:

Net force exerted = ?

Solution:

According to newton's second law of motion "the acceleration of a body is directly proportional to the force on it and inversely proportional to the mass of the body"

     a  =

F is the net force, a is the acceleration and m is the mass

Acceleration is the change in velocity of a body with time;

       a =

V is the final velocity

U is the initial velocity

t is the time taken

       since the boat starts from rest, initial velocity = 0

  Final velocity;

             V =

Now,

                F = ma

   In linear motion;

             s= ut + a t²

               t = 2.2min to seconds = 2.2 x 60 = 132s

s = distance covered

              5250 = 0 x 131   + x a x 132²

               5250 = 8712a

                    a = 0.6m/s²

           Since  F = ma

               F = 3460 x 0.6 = 2085.06N

Question 2:

Given parameters:

Force = 2400N

time taken = 36s

Mass = 35000kg

Unknown:

Final velocity = ?

Solution:

 According to newton's second law;

              F = ma

     F is force

     m is the mass

     a is the acceleration

         a =

        V is final velocity

         U is initial velocity

         t is the time taken

Since U = 0;

         a =

         F = m x

        2400 = 35000 x

            V = 2.47m/s

c. newton's third law of motion