Force – Pushing it in a Pulled up World
In the world of safety, we all come across controversial questions like “Is Pulling the load easier than Pushing”? Or “Is pushing safer than pulling”?
At the workplace, I have always followed the mantra that heavy load should always be pushed to be moved. Now it is imperative that some readers will disagree to that conclusion and may refer to that calculation of force (as shown below) against relative motion at an angle where pulling the load is easier due to reduction of frictional force.
fc1= µ (mg + F SinѲ)
fc2= µ (mg – F SinѲ)
But, if that is true why do we prefer to push a car when it is out of gas in the middle of the road? Why do we prefer to push a lawn mower or piece of furniture, when we know that it will be easier to pull? Some may say that pulling a load on wheels may have a potential to run you over and others say that pulling will restrict your vision of path to be followed.
The truth is that the aerodynamics of our body prefers the push posture as the component of self weight (WSinѲ) will act as an aid to the applied force by acting in the same direction. Whereas in the pull posture, our body weight will act against the applied force compelling the body to bend forward until the applied force is below the horizontal line.
There are many ways to interpret this theory or practice. However, from an EHS point of view, it is important to understand and assess the risk involved with each task in order to determine the correct method (pulling or pushing). What is your opinion?