Mr Pearce's Mechatronics Blog

Pulleys and Levers A pulley works like a lever. You can use them to reduce the force needed to move an object but the payoff is that you need to pull more rope through the pulley or move the end of the lever further. Force x Distance = Word Done (which is the same as energy, which can't be created or destroyed) So if you arrange the rope to go around the pulleys such that there are 4 lengths of rope that get shorter when the load moves up (both of these diagrams are the same arrangement) we will need to shorten the rope by 4 times the distance the load moves up. So the force on the rope will be a quarter of the load. The quarter load balances the 4 times distance.

Thinking is HARD (especially period 5 on a Monday) Today I asked my class to investigate how far the end of a lever moved and how it was related to where the pivot was. Their first suggestion as to how we could find this out was to go straight to Google!!!!! After an explanation about cardboard and skewers and several diagrams on the board the idea of being systematic about gathering data seemed alien to them. "How do I measure this," was a frequent question and the answer "That's a good question, how do YOU measure it?" was greeted with quizzical looks. In 40 minutes one group of two had about 5 results, a singleton had several results, a trio had none and a group of seven had 2 results. A couple of groups had opened up Google Sheets to record their results which could lead to good things. Here are my results

Degrees of Freedom Each different motion is a degreee of freedom. These can be linear or rotational. Linear is moving in a direction: Forward and backward is one degree of freedom, side to side is another. Rotational is turning at a point. Turning your head left and right is one degree of freedom, nodding your head up and down is another. The number of pieces of information needed to specify the position and state of the object we are talking about is the minimum number degrees of freedom in that system. A child on a swing has one degree of freedom. If you know the angle the swing has moved from the start position you know exactly where the child is. A position of a box of tissues on a desk has 2 degrees of freedom. If you know how far it is from the side of the desk and how far it is from the front of the desk you know where it is. Or you could know the angle it makes with the front of the desk, as measured from a particular corner and how far along that line it is - still 2 Do

Wow...I made a blog and this is my first post. I've never made a blog before so I'm interested to see how this can work for keeping track of work, learning and gathering evidence. In the first lesson we played with syringes. Found that air is squashy -  compressible  and water was not -  incompressible . We also found that you can make a popping noise. This is because the air molecules are far apart and so can be squashed together whereas the water molecules are already close together and so can't be squashed any further. Pneumatics is the use of air to power machines Can be cheap as air  is free Doesn't contaminate product so good for food processing applications Good for quick movements as air is low density Hydraulics is the use of liquid to power machines Precise movements as fluid is incompressible Can transfer greater force Oil can lubricate parts whilst moving them Some fluids are toxic Some fluids can operate at high temperatures (such as brak