1 Conservation of linear momentum: If the net external force acting on system of objects is zero, the vector sum of the momenta of the objects will remain constant. In collisions and explosions, the vector

7 Work and Energy 50m×9.8m/s2 ×0.10 = 7.0m/s. Suppose a constant force Fx acts in the +x−direction and causes an object to move a distance of ∆x. The work-done by the force is defined as W =fx∆x. The SI

5 Newton’s Laws of Motion Dynamics, the study of how forces influence motion, is involved in understanding a wide range of phenomena. Newton’s first law of motion: An object at rest will remain at rest;

1 Kinetic Energy W =1 2 kx2 = 1 2(640)(0.02)2 = 0.128J Suppose that a single constant force F acts on a particle in its direction of motion and causes it to accelerate, increasing in speed from an initial