# Selina Concise Class 6 Physics Inside Question Answer – Simple Machines

## Simple Machines : Selina Concise Class 6 Physics Inside Question Answer

Selina Concise Physics Class 6 Inside Based Question Paper with All Answer. Now of days for ICSE Class 6 Students, it is not enough to Learn only Exercise Questions Answers. As because most of the time Examiners will give Inside Question Answer from that respective Chapter. So Here in this page Our Experts provided All Selina Concise Class 6 Physics Inside Questions & Answers – Simple Machines.

#### (1) When we can say work is done and not?

Ans. Work is said to be done if the force applied on the body moves it. If no motion or change in motion takes place, no work is said to be done.

#### (2) What is Energy? What is the SI unit of work and energy?

Ans. Energy is the quantitive property that must be transformed to an object in order to persorm work on or to he3at the object.

The SI unit of work and energy is Joule.

#### (3) What is a Machine.

ans. A machine is a device which help us to do work more easily by applying less force and spending less energy.

#### (4) Write down the Principle of a Machine.

Ans. A machine does not work by itself. When energy is supplied to it, it does some usefu; work on a machine, a force is applied. This applied force is called the effort. As a result of its force the machine exerts a force to do work. This force is called the Load.

#### (5) Write down the formula of efficiency of a Machine.

Ans. Useful work done by the machine.

Efficiency = On the Load/ Work done on the machine by the effort.

#### (6) Define a lever and Write Classes of levers.

Ans. A lever is a simple machine which we most commonly use in our daily life. In Simple form, a lever is a rod which can turn about a fixed point called fulcrum.

Levers are divided into three classes depending on the position of the fulcrum, effort and load. They are –

(i) Class I Lever

(ii) Class II Lever

(iii) Class III Lever.

#### (7) Write down the formula of mechanical advantage of a lever. How the M.A increase of Lever.

The M.A of a lever can be increased by increasing the effort arm or reducing the Load arm.

#### (8) What is a Pulley? Write down the M.A of a Pulley.

Ans. A Pulley consists of a circular disc made of a metal or word. It is a Simple machine by which the direction of effort is changed to raise up a Load.

M.A of Pulley

= 1

#### (9) Define Wedge with examples.

Ans. A Wedge is a simple machines having a shart edge which is formed by putting two inclined planes together.

Examples :- Knife, Axe, Needle, Nail etc.

#### (10) A machine required an effort of 10 kgf for a load of 50 kgf. Find its mechanical advantage.

Ans. Here, Load = 50 kgf;

Effort = 10 kgf

= 50/10

= 5

### Selina Concise Class 6 Physics Exercise Questions & Answers

Ch. 1: Matter

Chapter 2: Physical Quantities and Measurement

Ch 3: Force

Ch 4: Sample Machines

Chapter 5: Light

Ch 6: Magnetism

Updated: April 9, 2020 — 5:36 pm