The only force acting on a 2.0-kg object moving along the x axis is shown.If the velocity v_x is −2.0 m/s at t = 0,what is the velocity at t = 4.0 s? A)−2.0 m/s B)−4.0 m/s C)−3.0 m/s D)+1.0 m/s E)+5.0 m/s

Question

Quizplus · Accepted Answer

According to Newton's second law, F = ma, where F is the net force acting on the object, m is the mass of the object, and a is the acceleration of the object. Since the diagram shows only one force acting on the object, we know that this is the net force. The force is acting in the negative x direction, so the acceleration of the object is also in the negative x direction. Using the equation v = v0 + at, where v is the final velocity, v0 is the initial velocity (given as -2.0 m/s), a is the acceleration (found from the force and mass), and t is the time (given as 4.0 s), we get v = -2.0 m/s + (-3.0 m/s^2)(4.0 s) = -14.0 m/s. Therefore, the velocity at t = 4.0 s is -3.0 m/s, so the answer is choice C.

The Only Force Acting on a 2