What is Force?
Force is a push or a pull that, when acting on an object, tends to cause a change in its state of motion. Specifically, a net force applied to an object will cause it to accelerate linearly (change its speed or direction of movement) according to Newton's Second Law of Motion (F=ma). Force is a vector quantity, meaning it has both magnitude and direction, and its standard unit is the Newton (N).
What is Torque?
Torque, often called the 'moment of force,' is a twisting force that tends to cause an object to rotate about an axis or pivot point. It is the rotational equivalent of linear force. For an object to rotate, a force must be applied at some distance from its axis of rotation, and this distance, combined with the perpendicular component of the force, determines the magnitude of the torque. Torque is also a vector quantity, measured in Newton-meters (N·m).
Key Differences and Relationship
The primary difference is their effect: force causes linear motion, while torque causes rotational motion. A force can exist without causing torque if it acts directly through an object's center of mass or pivot point. Conversely, torque cannot exist without an applied force; it requires a force acting at a distance from an axis. While force dictates translational acceleration, torque dictates angular acceleration.
Practical Examples of Force vs. Torque
Consider pushing a heavy box across the floor: you are applying a force to cause linear movement. Now, imagine using a wrench to tighten a bolt: you apply a force to the wrench handle, but it's the torque generated by this force acting at a distance from the bolt's center that causes the bolt to rotate and tighten. A car's engine generates torque, which is then converted into force at the wheels to propel the car forward.