Machines Class-10 Goyal Brothers  ICSE Physics Solutions Chapter-3 Machines . We Provide Step by Step Answer of Exercise, MCQs, Numericals Practice Problem Questions of Exercise-1 Machines ICSE Class-10 . Visit official Website CISCE  for detail information about ICSE Board Class-10 Physics.

## Machines Class-10 Goyal Brothers ICSE Physics Solutions Ch-3

-: Select Topics :-

Exercise-1

MCQ -1

Numericals Practice Problems-1

Exercise-2

MCQ -2

Numericals Practice Problems-2

### Exe-1 Machines Class-10 Goyal Brothers ICSE Physics Solutions Ch-3

Page-37,38

Question 1.
(a) What is a machine ?
(b) State three functions of machine.
(a) Machine : “Is a device which is used to transmit force to change the direction of force or to obtain speed.”
(b) Functions of machines :

1. To act as force multiplier
2. To shift the point of application to a convenient place.
3. To multiply speed.
4. To change the direction of the force applied for greater ease and comfort.

Question 2.

(a) Name six simple machines.
(b) Give one practical example of each machine named in (a)

(a) Simple machines are :

1. Lever
2. Pulley
3. Wedge
4. Inclined plane
5. Wheel and axle
6. Screw

(b) Example of :

1. Liver : is handle of common water pump helps in multiplying effort
2. Pulley : gears, used for changing the direction of the effort
3. Wedge : axe, A knife are the examples.
4. Inclined plane : Ramp or staircase or screw jack.
5. Wheel and axle : Free wheel or crank wheel of bicycle.
6. Screw : Screw bolt.

Question 3.
Define the following terms with reference to a machine

(c) effort
(d) ideal machine
(g) velocity ratio
(h) efficiency

(a) Total load : Load lifted by machine + resistance over come.
(b) Useful load : “The load, a machine in able to lift.”
(c) Effort : The effort applied by us on the machine.
(d) Ideal machine : A machine whose parts are weightless and frictionless such that what so ever is the energy spent on it same is the energy produced by it, is called a perfect machine.”
(e) Ideal mechanical advantage : “The ratio between total load moved (or resistance overcome) to the effort applied is called ideal mechanical advantage.”
(f) Actual mechanical advantage : “The ratio between useful load moved to the effort applied is called actual mechanical advantage”.
(g) Velocity ratio : [V.R.] : “Is the ratio of velocity of effort to velocity of load.”
i. e “Ratio of effort arm to load arm.”
(h) Efficiency : (η) “Efficiency of a machine is the ratio of useful work done by machine to the work put into the machine by the effort.”

Question 4.
Prove that efficiency of a machine is the ratio between mechanical advantage and velocity ratio.
Relation Between M.A., V.R And Efficiency :  Question 5.
Give two reasons, why machine cannot be 100% efficient.

1. Apart of input is always used in moving the parts of machine.
2. A part of input is wasted in overcoming friction between various parts of machine.

Question 6.
(a) Define lever. What are its kinds ?
(b) How will you determine the order of a lever ?
(a) Lever : “Is a straight or bent rigid rod which can turn about a fixed point called fulcrum”
(b) Out of effort (E), Load (L) and Fulcrum (F), the one which is in between the other two determines the order of lever i.e.
If F is in between L and E, then it is lever of 1 st order
If L is in between F and E. It is of second order lever.
If E is in between L and F, it is Illrd order lever.

Question 7.
To which order do the following levers belong and why ?

(a) A railway signal
(b) A man cutting bread with a knife
(c) A boy writing a piece of paper
(d) A nut cracker
(e) handle of a water pump
(f) see-saw
(g) forceps
(h) A man rowing a boat
(i) A lock and key
(j) Soda water opener
(k) a door
(l) motorcarfoot brake
(m) fishing rod
(n) lemon squeezer.

(a) A railway signals – Lever of 1st order as F is in between load and effort
(b) Cutting a bread with knife is third order lever as effort is in between load and fulcrum. (c) A boy writing a piece of paper is Illrd order lever as effort is in between load and fulcrum.
(d) A nut cracker is II nd order lever as load is in between effort and fulcrum. (e) Handle of water pump : 1st order lever as fulcrum is in between effort and load (f) See-saw : Lever of 1st order as fulcrum is in between load and effort (g) Forceps : Illrd order lever as effort is in between fulcrum and load. (h) A man rowing a boat : End order of lever as load is in between effort and fulcrum (i) Bottle Opener : Ilnd order lever as load is in between fulcrum and effort. (j) Soda – water opener : 2nd order lever as load is in between fulcrum and effort.
(k) A door : Ilnd order lever as load is in between effort and fulcrum.
(l) Motorcar foot brake : 3 rd order lever as effort is in between load and fulcrum. (m) A fishing rod : 3 rd order lever as effort is in between fulcrum and load.
(n) Lemon squeezer : 2 nd class lever as load is in between fulcrum and effort. Question 8.
Why does a lever of second order have mechanical advantage more than one ?
M.A. of second order of lever is more than one as effort arm is longer than load arm M.A = Effort arm / Load arm

Question 9.
Why does a lever of third order have a mechanical advantage less than 1 ?
M.A. of Illrd order lever is always less than 1 as effort arm is less than load arm M.A. = Effort arm / Load arm

Question 10.
In which situation does the lever of first order have mechanical advantage (a) more than 1 (b) less than 1 ?

(a) Mechanical advantage can be more than 1 when effort arm is larger than load arm or by moving the fulcrum towards the load.
(b) M.A. can be less than lwhen effort arm is smaller than load arm or by moving fulcrum towards effort.

Question 11.
Why are cutting edges of pliers smaller than the cutting edges of scissors ?
Cutting edges of pliers are smaller to make it force multiplier. Load arm is kept very small because the resistance (load) of the metal is very large and to over come this resistance the effort arm is made larger.

### Multiple Choice Questions-1

Machines Class-10 Goyal Brothers  ICSE Physics Solutions

1. Which of the statement is not true for a machine ?
(a) It can multiply force
(b) It can increase speed
(c) It can change the direction of applied force.
(d) Its output can be more than input.