In: Physics
Starting at time t=0, net force F1 is applied to an object that is initially at rest. If the force remains constant with magnitude F1 while the object moves a distance d, the final speed of the object is v1. What is the final speed v2 (in terms of v1) if the net force is F2=2F1 and the object moves the same distance d while the force is being applied? Express your answer in terms of v1.
The kinetic energy of an object of mass m moving at speed v is
The work done by a force F to move an object by a distance d is
By work energy theorem, the change in kinetic energy of an object is equal to the net work done on the object
Given the object starts from rest, the initial kinetic energy of the object is zero.
In the first case force F=F1 and final speed of the object is v=v1
In the second case force F=F2=2F1 and final speed of the object is v=v1
Dividing this by equation (1) we get