Newton's Laws - Mission NL8 Detailed Help


Consider the free-body diagram shown below. Use the numerical value for the individual forces and the approximate value of g (10 m/s/s) to determine the acceleration of the object (in units of m/s/s). Assign a negative number to the acceleration if it is ...


 
The relationship between net force (Fnet), mass (m) and acceleration (a) is expressed by the equation
 
Fnet = m•a


 
The mass of an object is mathematically related to its weight (or force of gravity) by the equation:
 
Weight = Fgrav= mass • g
 
where g is the acceleration caused by gravity alone. The value of g on Earth is 9.8 m/s/s (approximately 10 m/s/s).


 
The acceleration of an object can be found as the ratio of the net force to the mass. Thus, the solution to this question involves three steps:

Step 1: A free-body diagram depicts the individual forces acting upon an object. If all such forces are known, the net force can be determined by adding them up as vectors. If an upward and downward force are of equal value, then they will add as vectors to 0 N. The rightward and leftward forces can be added together as vectors by simply assigning the leftward force a negative value and then adding them up.

Step 2: The mass of an object is related to the force of gravity which acts upon it. Knowing the force of gravity (Fgrav), the mass can be found using the appropriate equation. (See Formula Frenzy section.)

Step 3: Determine the acceleration by taking the ratio of the net force to the mass. The direction of the acceleration is the same as the direction of the net force. Enter your answer with a - sign to indicate a leftward net force and acceleration; this is simply a mathematical convention used to indicate a leftward direction and infers nothing about the number being less than 0.