Class 5 Science Question Answers - Work, Force, Energy and Simple Machines

Q1: What is force, and how does it relate to doing work?
Ans: Force is a push or pull that is applied to an object. It is essential for making things move. When force is applied to an object to cause movement, work is done.

Q2: Explain the different effects of force with examples.
Ans: Force can have various effects on objects, including:

• Moving a stationary object: For example, pushing a car to get it moving.
• Increasing the speed of a moving object: For instance, pedalling harder on a bicycle.
• Changing the direction of a moving object: This can be seen when kicking a ball.
• Stopping a moving object: For example, applying brakes on a bicycle.
• Slowing down a moving object: An example would be using friction to reduce a car's speed.

Q3: What are the different types of forces mentioned in the text, and provide examples of each.
Ans: The different types of forces include:

• Gravitational force: This is observed when objects fall to the ground.
• Magnetic force: This occurs when magnets attract iron.
• Muscular force: This is the force exerted when pushing or pulling an object.
• Electrostatic force: This is seen when charged materials attract or repel each other.
• Frictional force: This force acts to stop or slow down objects when they are in contact.

Q4: What are the various forms of energy and how are they useful in our daily lives?
Ans: The various forms of energy include:

• Light energy: essential for seeing objects.
• Heat energy: derived from sources like the sun or burning fuels.
• Sound energy: produced by devices and living organisms.
• Electrical energy: used in various appliances.
• Mechanical energy: associated with an object's position or movement.

These forms of energy are essential for numerous aspects of our daily lives.

Q5: Explain the concept of simple machines. How do they make work easier?
Ans: Simple machines are tools with a straightforward structure that make work easier and faster. They do this by either changing the direction of force or increasing force. Examples include levers, wheel and axle, inclined planes, wedges, screws, and pulleys.

Q6: Describe the three types of levers and provide examples of each.
Ans: The three types of levers are:

• Class 1 Lever: The fulcrum is between the load and the effort (e.g., a seesaw).
• Class 2 Lever: The load is between the fulcrum and effort (e.g., a wheelbarrow).
• Class 3 Lever: The effort is between the fulcrum and load (e.g., tweezers).

Q7: What is a wheel and axle? Give examples of wheel and axle devices.
Ans: A wheel and axle is a simple machine that consists of a wheel attached to a central axle. When the axle rotates, the wheel moves, facilitating easier movement of objects. 
Examples of devices that utilise the wheel and axle include:

• The steering wheel of a car
• A screwdriver
• A sewing machine
• A doorknob

Q8: Explain what an inclined plane is and provide examples of its use.
Ans: An inclined plane is a sloped surface that allows an object to be moved with less effort than lifting it directly upwards. This mechanical advantage makes it easier to elevate heavy items. Examples include ramps, staircases, slides, and hilly roads.

Q9: What is a wedge, and how is it used as a simple machine?
Ans: A wedge is a simple machine that consists of two inclined planes joined back to back, forming a V shape. It features at least one slanting side that ends in a sharp edge, allowing it to be driven into materials. Examples of wedges include nails, forks, knives, and axes.

Q10: What is a screw, and how does it increase force? Provide examples of screw devices.
Ans: A screw has grooves (threads) cut into it and is turned round and round with a screwdriver to insert it into objects. It increases force because it takes less effort to insert a screw than a nail. Examples include screw jacks, drilling machines, and nut bolts.