# Simple Machines And Their Importance ICSE Class-6 Goyal Brothers Physics Solutions Chapter-4 Unit-1

Simple Machines And Their Importance ICSE Class-6th Goyal Brothers Physics Solutions Chapter-4, Unit-1. We Provide Step by Step Answers of Objective, True False, Incorrect and Correct, Fill in the blanks, Match the following , Study Questions of Chapter-4, Energy, Unit-2 (Simple Machines And Their Importance). Visit official Website  CISCE  for detail information about ICSE Board Class-6.

## Simple Machines And Their Importance ICSE Class-6 Goyal Brothers Physics Solutions Chapter-4 Unit-1

 Board ICSE Class 6th Subject Physics Book Name Goyal Brothers Chapter-4 Energy Unit-1 Simple Machines And Their Importance Topic Solution of exercise questions Session 2023-24

### OBJECTIVE TYPE QUESTIONS

(Simple Machines And Their Importance ICSE Class-6 Goyal Brothers Physics Solutions Chapter-4 Unit-1)

#### Que: A. Fill in the blank spaces by choosing the correct words from the list given below :

List : load, simple, less, direction, effort

1. The handle of a water pump acts as a simple machine.

2. The resistance overcome by a machine is called load.

3. A machine may simply change the direction of applied force.

4. The force applied on a machine to do some mechanical work is called effort.

5. In a machine the output is always less than the input.

#### Que: B. State whether the following statements are true or false :

 Statements True/False 1. Machines are used for doing dangerous works only. 2. The ratio between useful load lifted to the effort applied is called mechanical advantage. 3. The energy supplied to a machine in doing some mechanical work is called input energy. 4. The output energy of a good machine is always greater than input energy. 5. The ratio between the input energy to the output energy of a machine is called its efficiency.

 Statements True/False 1. Machines are used for doing dangerous works only. F 2. The ratio between useful load lifted to the effort applied is called mechanical advantage. T 3. The energy supplied to a machine in doing some mechanical work is called input energy. T 4. The output energy of a good machine is always greater than input energy. F 5. The ratio between the input energy to the output energy of a machine is called its efficiency. T

#### Que: C. Statements given below are incorrect. Write the correct statements.

##### 2. A machine which lifts more load than effort applied has efficiency more than 1.

Answer: A machine which lifts more load than effort applied has mechanical advantage efficiency more than 1.

##### 3. An ideal machine is possible in real life.

Answer: An ideal machine is impossible in real life.

##### 4. The force applied on a machine to do some mechanical work is called effort.

Answer: The force applied on a machine to do some mechanical work is called pressure.

##### 5. The ratio between input energy and output energy is called efficiency of machine.

Answer: The ratio between output energy and input energy is called efficiency of machine.

#### Que: D. Tick (√) the most appropriate answer :

##### 1.Which of the following do not belong to the same class ?

(a) Lever

(b) Pulley

(c) Inclined plane

(d) Wheel and axle

Answer: option (c) Inclined plane is correct.

##### 2. Which of the following do not belong to the same class ?

(a) inclined plane

(b) wedge

(c) pulley

(b) screw

Answer: option (c) pulley is correct.

##### 3. In an ideal machine the output energy is :

(a) more than input energy

(b) equal to input energy

(c) less than input energy

(d) infinite compared to input energy

Answer: option (b) equal to input energy is correct.

##### 4. The output energy of a real life machine is less than input energy because of :

(a) moving pats of machine

(b) friction at the moving parts

(c) both (a) and (b)

(d) none of these

Answer: option (c) both (a) and (b) is correct.

#### Que: E. Match the statements in Column A, with those in Column B :

 Column A Column B 1. A machine whose parts are frictionless as well as weightless. (a) Simple machine 2. In an device, output energy is less than input energy. (b) Ideal machine 3. The ratio between the output energy and the input energy. (c) Machine 4. The machine such as handle of water pump or a ramp. (d) Principle of machine 5. A device which may speed up work or move heavy load or change direction of effort. (e) Efficiency of machine

 Column A Column B 1. A machine whose parts are frictionless as well as weightless. (a) Ideal machine 2. In an device, output energy is less than input energy. (b) Principle of machine 3. The ratio between the output energy and the input energy. (c) Efficiency of machine 4. The machine such as handle of water pump or a ramp. (d) Simple machine 5. A device which may speed up work or move heavy load or change direction of effort. (e) Machine

### STUDY QUESTIONS

Simple Machines And Their Importance ICSE Class-6 Goyal Brothers Physics Solutions Chapter-4 Unit-1

##### Question: 1.(a) Define the term machine.

Answer: A device that helps lift a heavy load, speed up motion, or change the direction of the force in the desired direction is called a machine.

##### (b) Name six types of simple machines.

Answer: Six types of simple machines are Lever, Pulley, Inclined plane, Wedge, Screw, Wheel, and Axle.

#### Question: 2. Give four reasons for using machines.

Answer: Machines are used to :

1. Change the effort in the desired direction.
2. Speed up the motion of a body.
3. Lift a heavy load by applying a small effort.
4. Do unsafe and dangerous work.

#### Question: 3. What is an ideal machine ? State the principle of an ideal machine.

Answer: The principle of an Ideal Machine:

1. It is defined as a machine that converts all the input energy into useful output energy. The efficiency of the ideal machine is 100%.
2. The principle of the ideal machine is that the work done by the machine is equal to the work done on the machine.

#### Question: 4. The output energy of a real life machine is always less than the input energy. Give two reasons for this deficiency.

Answer: 1. The output work is always less than the input work because some input work is used to overcome friction.

2. Therefore, efficiency is always less than 100 percent. All machines make work easier, but they don’t increase the amount of work that is done.

3. Efficiency is the percent of work put into a machine by the user (input work) that becomes work done by the machine (output work).

4. The output work is always less than the input work because some input work is used to overcome friction.

#### Question: 5. Define the following terms :

##### Question: 6.(a) What do you understand by the term efficiency of machine ?

1. The efficiency of a machine indicates how well its input energy is converted to useful output energy or work.
2. It is a major factor in the usefulness of a machine and is the fraction or percentage of the output divided by the input.
##### (b) A machine has an efficiency of 70%. Explain the statements as clearly as possible.

1. If a machine is 70% efficient, it means that 70% of the work input to the machine is obtained as the useful work output.
2. The remaining 30% of the work input has been lost in overcoming the friction and other factors.

#### Question: 7. The physical quantities such as mechanical advantage and efficiency of machine has no units, but are pure numbers. Explain.

1. The physical quantities such as mechanical advantage and efficiency of the machine have no unit but are pure numbers.
2. It is because these physical quantities are ratios of quantities that have the same units.
3. These units cancel out each other.
4. Therefore, physical quantities such as mechanical advantage and efficiency of the machine have no unit but are pure numbers.

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