Notes, Exercises, Videos, Tests and Things to Remember on Simple Machine
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We use various types of machine in our daily life to perform various activities. These machines make our work easy and efficient. For example, we use a knife to chop vegetables, scissors to cut papers, beam balance to measure weight, bottle opener to open the bottle, etc. There are a simple machine and complex machine. Forceps, punching machine, crowbar, bottle opener, etc. are examples of the simple machine while motorcycle, truck, car, etc. are some examples of the complex machine. A simple machine is a device, which is simple in structure and makes our daily work easier, faster and more convenient.
Mainly, there are six types of simple machines, which are given below,
Lever is a type of simple machine that is used to lift the heavy loads. It is made of a rigid bar that moves about a fixed point called fulcrum. It consists of three parts, effort arm, fulcrum and load arm. Fulcrum is the point where rigid bar rotates. By applying effort in effort arm the load is lifted by the help of fulcrum. Effort arm is the distance between the fulcrum and the point where effort is applied and load arm is the distance between fulcrum and load where the load is kept. Input work is equal to output work in an ideal lever which is the balanced condition of the lever. It is the principle of the lever.
Levers are of three types depending upon the positions of fulcrum, load, and effort which are as follows,
Bring a rigid bar, one heavy stone, and two bricks. Then, lift the stone without using a rigid bar. Place stone in the one end of the bar and place the middle part of the bar in the bricks of a certain height. Then, apply the effort on the other end of the bar. What do you conclude from this experiment? What is the reason behind it?
A pulley is a simple machine consisting grooved circular disc and a rope. The rope passes over the circular disc. In pulley, a load is attached to one end of the rope while the effort is applied at the another end of the same rope. Here, the effort is applied in a convenient way which makes our work easier. There are two types of the pulley on the basis of their movements. They are as follows,
Lift the water from the well by using a pulley. The water bucket moves upward though you are pulling the rope downward. What do you conclude from this experiment? What is the reason behind this?
It consists of two cylinders having a different radius. Cylinder with a small radius is axle and cylinder with a large radius is a wheel. Formally, a rope is coiled in wheel and axle. The effort is applied in wheel and load in the axle. They move in the same manner but the distance covered is different due to the difference in radius. Since effort applied on the wheel is magnified so, by applying small effort on the wheel, heavy loads can be lifted. Some of the examples of wheel and axle are paddle of the bicycle, a drill used by carpenters, steering of vehicles, etc.
Ride and use the paddle of the bicycle. You can find that the tyres move faster though you paddle slowly. What do you conclude from this experiment? What is the reason behind this ?
It is very difficult to load heavy things onto a truck or some area of a certain height. A huge effort is needed. In such case, the inclined plane is used. It is a sloping surface or a wooden plank. It multiplies the applied effort. It helps to push the heavy load upward easily. The winding road, staircase, ladder, etc. are the examples of an inclined plane.
Bring a sloping surface or a wooden plank and a heavy load like a small drum. Then lift the drum up to the certain height without using the wooden plank. After this, again lift the drum in the same height by using wooden plank i.e. inclined plane. What do you conclude from this two activity? What is the reason behind it?
A screw is an inclined plane wrapped around a nail. It consists of circular edges called thread. The pitch is the distance between two screw thread. The effort is applied to the head of the screw. It looks similar to nail and requires less effort to insert into the wood. Screw, nail, jack screw, etc.are some of the examples of the screw.Jack screw is used to lift the vehicles up to the certain height.
Bring a screw and the wood. Then insert the screw in the wood by rotating its head instead of pressing it inside. The screw moves downward though we don’t press the screw. What is the reason behind it?
A wedge is a triangular shaped tool. Wedge consists of two or more sloping surfaces with one end sharp or pointed edge while the other one is a blunt edge. Here, the effort is applied at the blunt side. It is mainly used for cutting and splitting things, drilling holes etc. Some of the examples of wedges are axe, knife, nail, sickle, etc.
Bring a knife and a small piece of wood. Then cut the piece of wood with the help of the knife. Though you hit the piece of wood in the straight direction or apply force in one direction (vertical), the woods gets separated (horizontal force). What is the reason behind it?
Identify the simple machines given below. Classify them and write down their uses and types. What do you learn from this activity? Write down your conclusion.
Names of simple machine
Types of Simple machine
The importances of simple machine is as follows:
Any five types of simple machine with two example of each are given below,
A lever is a rigid bar which moves freely about a fixed point called the fulcrum. There are three types of lever which are as follows,
The work done on a machine is called the input work and the useful work done by the machine is called the output work. The principle of lever is given below,
In ideal lever when it is in balanced condition then,
Input work = output work
Or, Effort \(\times\) effort arm = Load \(\times) load arm.
A wedge is a simple machine having two or more sloping surfaces that taper either to form a sharp edge or pointed edge. Any three examples of wedge are axe, knife, and needle.
Any three advantages of using simple machines in our daily life are as follows,
A pulley is a simple machine having a grooved circular disc over which a rope passes. There are three types of pulley which are as follows,
A second class lever is a type of lever in which load is situated between the fulcrum and the effort. Since in bottle opener, the load ( bottle cork) is situated between the fulcrum and effort so the bottle opener is a second class lever.
Simple machines: Beam- balance, nut- cracker, flag pole, screw- driver, ladder, nail and axe.
The simple machines with their types are given below,
Any five simple machines used in our homes are as follows,
In second class lever, load is situated between the fulcrum and the effort and in third class lever the effort is situated between the fulcrum and the load. Since in shovel, the effort is situated between the fulcrum and load so it is called third class lever but not a second class lever.
Which one of them is a example of second class lever ?