A flea jumps by exerting a force of 1.20×10−5 N straight down on the ground. A breeze blowing on the flea parallel to the ground exerts a force of 0.500×10−6 N on the flea. Find the direction and magnitude of the acceleration of the flea if its mass is 6.00×10−7 kg . Do not neglect the gravitational force.

Solution 40PE

Step 1 of 8</p>

Breeze blowing parallel to the ground, by exerting a force of on a flea with mass , when the flea jumps with a force of straight down the ground. Here we need to calculate the direction and magnitude of the flea by including the gravitational force.

We can calculate the net force using the free body diagram of the flea. Then by using the calculated net force, we can estimate the direction and magnitude of acceleration using Newton’s second law.

Step 2 of 8</p>To draw the free body diagram of flea,

The horizontal force that acts on the flea is due to the breeze, therefore the net horizontal force is

…………...1

Step 3 of 8</p>To calculate the net vertical force,From the above FBD of flea, a downward force called weight acts on flea due to mass of flea. The weight of the flea is given by,

……...2

Where is weight of flea, is mass of flea, is acceleration due to gravity.

Also a normal force acts on the flea , which is equation in magnitude to the force that is applied by the flea on the ground.That is , ……..3

The net vertical force on the flea () is resultant of above two forces,

Using equation 2 and 3,

Step 4 of 8</p>

Substituting , and in above equation

Using

……….4