Test: Work, Force, Energy And Simple Machines - 2 - Class 5 MCQ

The correct statement regarding the lever is:
(i) In beam balance, fulcrum is in the middle.
(iii) In tongs, the fulcrum and the load are at two ends.
(iv) Sea-saw is an example of first class lever.
Let's discuss each statement in detail:
(i) In beam balance, fulcrum is in the middle:
- A beam balance is a type of lever where the fulcrum is located in the middle.
- This allows for equal distribution of weight on both sides of the fulcrum, making it easier to compare the weights of two objects.
(iii) In tongs, the fulcrum and the load are at two ends:
- Tongs are a type of lever where the fulcrum is located at one end and the load (the object being lifted or held) is at the other end.
- The effort is applied in the middle to squeeze the tongs and hold the load.
(iv) Sea-saw is an example of first class lever:
- A sea-saw is a classic example of a first-class lever.
- The fulcrum is located in the middle, and the effort (the force applied) and the load (the weight being lifted) are on opposite sides of the fulcrum.
- When one person pushes down on their side, the other side goes up, creating a balancing motion.
Therefore, the correct statement is (i), (iii), and (iv).
Answer: A. (i), (iii), and (iv)

A pulley can be of two types: fixed pulley and movable pulley. Fixed pulleys are attached to a support, while movable pulleys are used in combination with fixed pulleys to lift heavy loads.

When carrying sharp and pointed tools like a knife, position the pointed edge downward and handle it with care to avoid accidents.

Muscular force is applied when we push or pull something using our muscles. A boy pushing a bicycle is an example of muscular force.

A fishing rod uses both a wheel and axle (for the reel) and a lever (the rod itself).

The correct answer is A: Mechanical energy.
Explanation:
To move the wheeled trolley, mechanical energy is required. Mechanical energy is the energy possessed by an object due to its motion or position. In this case, the trolley needs to overcome forces such as friction and gravity to move.
Here is a detailed explanation of each option:
1. Mechanical energy: This is the energy associated with the motion or position of an object. In the case of the wheeled trolley, mechanical energy is required to overcome the forces acting against its motion and move it. It can be in the form of kinetic energy (energy of motion) or potential energy (energy due to position).
2. Electrical energy: Electrical energy is the energy associated with the flow of electric charge. While electrical energy may be used to power the motor of the trolley, it is not the primary form of energy required to move the trolley itself.
3. Solar energy: Solar energy is the energy derived from the sun. Although solar energy can be converted into other forms of energy, such as electrical energy, it is not directly used to move the wheeled trolley.
4. Heat energy: Heat energy is the energy associated with the random motion of particles. While heat energy may be generated during the movement of the trolley due to friction, it is not the energy required to initiate and sustain the motion of the trolley.
In conclusion, the primary form of energy required to move the wheeled trolley is mechanical energy.

- When a ball is thrown upward, it moves against the force of gravity.
- Gravity is a natural force that pulls objects toward the center of the Earth.
- As the ball rises, it slows down until gravity overcomes its upward motion, causing it to fall back down.
- This is why the correct answer is B: Gravitational force.
- Without gravity, the ball would not come back down; it would continue to move indefinitely in the air.

Ensuring the moving parts of machines are well lubricated helps prevent accidents and ensures smooth operation. Additionally, sharp tools should be handled with care and stored properly.

Potential energy is the energy stored in an object because of its position or configuration.

The lid of a jar is a screw, which is a type of simple machine.
Explanation:
The lid of a jar is designed to be twisted on and off, which is made possible by the presence of threads on both the lid and the jar. This threading mechanism allows the lid to be securely fastened and sealed onto the jar, preventing the contents from spilling or spoiling.
Characteristics of a screw as a simple machine:
- A screw is an inclined plane wrapped around a cylinder or cone.
- It has a helical groove, known as threads, running along its length.
- The rotation of the screw converts linear force into rotational force.
- The pitch of the screw determines the mechanical advantage it provides.
Advantages of using a screw as a lid for a jar:
- The threading mechanism of a screw allows for a secure and airtight seal, preventing leakage or contamination of the contents.
- It is easy to open and close the jar by twisting the lid, providing convenience to the user.
- The mechanical advantage provided by the threads allows for a greater force to be applied while tightening or loosening the lid.
Overall, the lid of a jar can be classified as a screw, which is a type of simple machine. Its design and functionality make it an effective tool for sealing and preserving the contents of the jar.

Explanation:
The lever is a simple machine that consists of a rigid bar that is free to rotate around a fixed point called the fulcrum. It is used to amplify or redirect force.
Let's analyze each activity to determine if it involves the use of a lever:
(i) Using your arm to lift a handbag:
- In this activity, your arm acts as a lever, with the elbow joint acting as the fulcrum.
- When you lift the handbag, the biceps muscle contracts, applying an upward force on the forearm, which acts as the effort force.
- The load force is the weight of the handbag acting downwards.
- The forearm acts as a lever, with the elbow joint as the fulcrum, to overcome the load force and lift the handbag.
(ii) Using scissors to cut clothes:
- Scissors consist of two blades joined together at a fulcrum.
- When you squeeze the handles of the scissors, the blades pivot around the fulcrum, creating a cutting motion.
- The effort force is applied by your fingers, and the load force is applied by the material being cut.
- The blades of the scissors act as levers, with the fulcrum at the pivot point, to cut through the material.
(iii) Using a wheelbarrow to transfer tools:
- A wheelbarrow consists of a long handle, a wheel, and a shallow container for carrying items.
- When you push the wheelbarrow, the handle acts as a lever, with the wheel as the fulcrum.
- The effort force is applied by your arms, and the load force is the weight of the tools and the wheelbarrow itself.
- The handle of the wheelbarrow acts as a lever, with the wheel as the fulcrum, to transfer the tools.
Therefore, all of the given activities involve the use of a lever. The correct answer is D: All of these.

- A sea-saw operates as a first class lever, where the fulcrum is positioned between the effort (where one person pushes down) and the load (the other person).
- The key characteristics of a first class lever include:
- Fulcrum: Located between the effort and load.
- Mechanical Advantage: It can change the direction of the applied force.
- Examples of first class levers include scissors and seesaws, where balance is achieved by adjusting the position of the load relative to the fulcrum.

Class 3 levers have the effort located between the fulcrum and the load, and are used to decrease force to carry out delicate work, such as with tweezers and tongs.

The sun is not a direct source of electrical energy, though it is a source of solar energy. Electrical appliances like fans, washing machines, and computers use electrical energy generated at power stations and supplied to our homes through wires.

Explanation:
The surface of the ramp is made smoother because, there would be less friction opposing the box. Here's a detailed explanation:
Friction:
Friction is a force that opposes the motion of objects in contact with each other. When a box is being loaded onto a truck ramp, friction between the box and the ramp surface can make it difficult to push or slide the box. This friction force acts in the opposite direction of the applied force, making it harder to move the box.
Smooth Surface:
By making the surface of the ramp smoother, the amount of friction between the box and the ramp is reduced. A smooth surface allows the box to slide more easily, requiring less force to move it. This is because a smooth surface reduces the amount of roughness or irregularities that can cause the box to stick or catch on the ramp.
Less Friction:
With less friction opposing the box, it becomes easier to push or slide the box onto the truck ramp. This is beneficial when loading multiple boxes onto the truck, as it reduces the effort required and increases efficiency.
Conclusion:
So, the surface of the ramp is made smoother to reduce the friction opposing the box, making it easier to load the boxes onto the truck ramp.