Force Work Power and Energy

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Class 10 Physics Chapter 1
Force, Work, Power and Energy
Important Questions

The ideas of force, work, power, and energy are essential building blocks in the field of physics that enable us to comprehend and measure the interactions and changes that occur in the physical world. These ideas are fundamental to understand object behavior, motion mechanics, and the capacity to carry out a range of jobs and activities. Let’s investigate these ideas that form the basis of our comprehension of the physical universe and how they relate to each other to explain the dynamics of motion and the transfer of energy in everyday life as we delve into the realm of ICSE Class 10 Physics. Comprehending the concepts of force, work, power, and energy is crucial not just for achieving scholastic success but also for understanding the laws governing the real-world occurrences we encounter. Here you will find class 10 Force, Work, Power and Energy important questions and answers.

Introduction

In this chapter on Force, Work, Power, and Energy in ICSE Class 10 Physics, we will delve into the core concepts that drive our understanding of the physical world. This chapter covers key concepts: force—what it is and how it’s measured; work—the application of force over a distance; power—the rate of doing work or transferring energy; and energy—its forms, transformation, and conservation principles. Understanding these fundamentals helps explain motion and everyday phenomena in the world around us. If you want to prepare well then below are some ICSE class 10 physics force questions and answers.

What are Force, Work, Power and Energy?

Force is an external agent capable of changing a body’s state of rest or motion. It has a magnitude and a direction. The direction towards which the force is applied is known as the direction of the force, and the application of force is the point where force is applied. Work is referred to as the process of energy that is transferred to an object’s motion by applying force. It is generally represented as the product of displacement and force. Energy, in physics, the capacity for doing work. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms. If you want to practice more questions and clear your understanding, then oswal.io provides you with Class 10 Force, Work, Power and Energy important questions and answers.
important questions for class 10 icse physics

Class 10 Force, Work, Power and Energy Important Questions and Answers

Q1. For a given mass if kinetic energy increases 16 times the momentum :
Options
(a) increases four times
(b) increases twice
(c) decreases four times
(d) decreases twice

Ans. (a) increases four times

Explanation:
Kinetic energy and momentum mathematical expression is defined is-
\text{K.E } = \dfrac{1}{2} \text{mv}^2 \\[4.5 bp] \rArr \text{K.E = } \dfrac{1}{2} \text{mv}^2 × \dfrac{m}{m} = \dfrac{(mv)^2}{2m} \\[4.5 bp] \rArr \text{K.E = } \dfrac{P^2}{2m} \text{(∵ Momentum,P = mv)}\\[4.5 bp] \rArr P = \sqrt{2m(k. E.)}\\ Now, new kinetic energy. K.E’=16 K.E.
\\\text{New, linear momentum, P = }\sqrt{2m(k.E.)} = \sqrt{2m(16 k.E.)} \\[4.5 bp] \rArr P = 4 \sqrt{2m(k.E.)}\\[4.5 bp] \rArr P = 4 P [\because P = \sqrt{2m(k.E.)}]

Q2. The weight of a uniform half meter scale would act at ................ mark.
Options
(a) 25 cm
(b) 50 cm
(c) 0 cm
(d) 100 cm

Ans. (a) 25 cm

Explanation:
Given, uniform meter rule, so weight (Mg) will act at 25 cm. Mg produces anticlockwise moment about point o

Q3. (i) Define power.
(ii) Is power a scalar or vector quantity?

Explanation:
(i) Power is the rate at which work is done or energy is transferred or converted. In physics, it is typically measured in watts (W) and is the amount of energy or work done per unit of time. Mathematically, power (P) is defined as:

P = W / t

Where:
P = Power (in watts, W)
W = Work done or energy transferred (in joules, J)

t = Time (in seconds, s)

(ii) Power is a scalar quantity. This means that it has magnitude but no direction. Unlike vector quantities, which have both magnitude and direction (such as force or velocity), power is only concerned with how much energy is transferred or work is done per unit of time, without specifying a particular direction.

Q4. A satellite revolves around a planet in a circular orbit. What is the work done by the satellite at any instant ? Give a reason.

Explanation:
The work done by a satellite in a circular orbit around a planet is equal to zero. This is because work is defined as the product of the force applied and the displacement over which the force is applied, and the displacement for an object moving in a circular orbit is always perpendicular to the force acting on it.

In the case of a satellite in a circular orbit, the gravitational force between the satellite and the planet provides the centripetal force required to keep the satellite in its circular path. The centripetal force always acts perpendicular to the direction of motion, which means that the displacement of the satellite is also perpendicular to the force.

Work done (W) is calculated using the formula:

W = F * d * cos(θ)

Where:
W is the work done
F is the force applied
d is the displacement
θ is the angle between the force and the direction of motion.
Since θ is 90 degrees (perpendicular), the cosine of 90 degrees is 0, which means that the work done in a circular orbit is zero. Therefore, the satellite does no work on itself as it revolves in a circular orbit around the planet, and the work done by the satellite is also zero.

Q5. What is meant by equilibrium and state the conditions of equilibrium of a body?

Explanation:
When a number of forces acting on a body produce no change in its state of rest or of uniform motion, the body is said to be in equilibrium.
The two conditions of equilibrium of a body:
(i) The resultant of all the forces acting on the body should be equal to zero.
(ii) The algebraic sum of moments of all the forces acting on the body about a point should be zero.

ICSE Class 10 Physics Chapter wise Important Questions

Conclusion

Force is the fundamental topic within the ICSE class 10 physics curriculum.. If you seek additional practice and a deeper comprehension of the topics covered in the chapter, oswal.io offers an extensive array of ICSE class 10 physics force questions and answers to facilitate a more profound understanding of the concepts.

Frequently Asked Questions

Ans: Force is an external agent capable of changing a body’s state of rest or motion. It has a magnitude and a direction. The SI unit for force is the Newton (N), which is equivalent to one kilogram-meter per second squared (kg·m/s²).
Ans: In physics, work is done when a force is applied to an object, and the object moves in the direction of the force. Work is calculated as the product of force and displacement in the direction of the force. The SI unit for work is the joule (J), which is equivalent to one newton-meter (N·m).
Ans: Power is the rate at which work is done or energy is transferred or converted. It measures how quickly work is performed. The SI unit for power is the watt (W), which is equivalent to one joule per second (J/s).
Ans: Energy is the ability to do work. It comes in various forms, including kinetic (associated with motion), potential (associated with position or stored energy), thermal, chemical, and many others. The law of conservation of energy states that energy cannot be created or destroyed but can only change from one form to another. The total energy in a closed system remains constant. There are various forms of energy, including kinetic, potential, thermal, chemical, nuclear, electrical, and more. Each type of energy can be converted into other forms.
Ans: Weight is a measurement of the force of gravity exerted on a body. Weight is measured in Newton.