# LAB PHY 4.docx - N T T W2 = m2g W1 = m1g Figure 4.1 Free...

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T N W2 = m2g T W1 = m1g Figure 4.1: Free body diagrams of the forces acting on (a) m 2 and (b) m 1 As shown in Figure 2 (a), there are three forces acting on m 2 ; the force from the contact of the frictionless surface pushing up on m 2 labelled T. The contact (normal) force and the gravitational force cancel each other, meaning the total force acting on along vertical direction on m 2 is equal to zero. This leaves the tension in the string as the total force acting on m 2 . Newton’s second law said that m 2 will accelerate and give the equation: T = m 2 a Figure 2 (b) shows that there are only two forces acting on m 1 namely the gravitational force, W = m 1 g in downward direction and the tension that pulls m 1 upward. By using Newton’s second law; F total = T m 1 g =− m 1 a Eliminating T from equation by substituting equation 2 into equation 3, a single equation for the acceleration is written as: m 2 a m 1 g =− m 1 a Which is Newton’s Second Law for a system of mass (m 2 +m 1 ) with net force applied to it is the equation of a straight line with a slope equal to the mass of the system, (m 2 +m 1 ). So, if you vary the mass of m 1 , keeping the gravitational force acting on the system and the acceleration system. Notice that the tension has been eliminated from the final equation and is not needed in the analysis since we are only concerned with forces acting on the system, not acting between objects within the system.
Acceleration, ( a ) can be determined using equation: x = v 0 t + 1 2 at 2
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