Different Types of Forces and Their Applications
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Force acting on the surface
1
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Surface Area
https://www.youtube.com/watch?v=E_JVpDJ2
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Q1 Identify the agent exerting the force
(a) squeezing a piece of lemon between fingers
(b)A person diving into the swimming pool
(c)A labourer moving a loaded cart
(d)An athlete making a high jump to clear a bar
kept at a certain height.
Answers will be discussed in the audio
Write the name of the chapter in the index
Date and name of the chapter on the new page
First you have to write the questions and answers
shared in this ppt (part D: Q4,6 & Part E Q b, e
and Q4 )
I will be sharing an audio to discuss other answers.
You need to sit with your book pages , pen and
copy. You will write the keywords as discussed in
the audio and frame your own answers.
Write questions of all answers being discussed in
the auio before the next class
Q4.
When we throw a ball upwards , what
happens to its speed while its going up and
why ?
Ans : The speed of the ball decreases
because the gravitational force pulls it down
towards the earth.
Q6. How would the pressure (exerted by a force)
change if :
(a) the area is doubled keeping the thrust constant
Ans : Pressure = thrust / Area
So, when area is doubled, pressure becomes half
(b) the thrust is doubled keeping the area constant
Ans : Pressure is directly proportional to thrust. So
it gets doubled.
Q3 b) Give reason why potters place a large round piece
of cloth on their heads when they carry heavy loads
Ans : i) pressure is inversely proportional to contact
area
ii) round cloth increases the contact area thereby
reducing the pressure.
e) It is easier to burst an inflated balloon with a needle
than with the finger
Ans i) pressure is inversely proportional to contact area
Ii)needle having lesser area of contact pricks the balloon
with more pressure.
Q4. Two rods A and B of the same weight and
equal length have different thickness. A boy
held them vertically on sand as shown in the
figure. Which one will sink less and why ?
Ans: i) Pressure is inversely
proportional to the area of
contact.
ii) Since rod B has more area , it will exert
less pressure on the sand and will sink less.
This content explores various types of forces including non-contact and contact forces such as gravitational, magnetic, electric, frictional, and muscular forces. It also discusses the effects of forces on different surfaces and provides examples of force application in real-life scenarios.
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Presentation Transcript
TYPES OF FORCES NON- CONTACT FORCES CONTACT FORCES (i)GRAVITATIONAL (ii)MAGNETIC (iii)ELECTRIC FRICTIONAL FORCE MUSCULAR FORCE
Force acting on the surface 1 --------------------- Surface Area
Buses & trucks are double wheeled Buildings & dams have a wide base Tanks and bulldozers have caterpillar wheels Railway tracks have wooden sleepers
Q1 Identify the agent exerting the force (a) squeezing a piece of lemon between fingers (b)A person diving into the swimming pool (c)A labourer moving a loaded cart (d)An athlete making a high jump to clear a bar kept at a certain height. Answers will be discussed in the audio
Write the name of the chapter in the index Date and name of the chapter on the new page First you have to write the questions and answers shared in this ppt (part D: Q4,6 & Part E Q b, e and Q4 ) I will be sharing an audio to discuss other answers. You need to sit with your book pages , pen and copy. You will write the keywords as discussed in the audio and frame your own answers. Write questions of all answers being discussed in the auio before the next class
Q4.When we throw a ball upwards , what happens to its speed while its going up and why ? Ans : The speed of the ball decreases because the gravitational force pulls it down towards the earth.
Q6. How would the pressure (exerted by a force) change if : (a) the area is doubled keeping the thrust constant Ans : Pressure = thrust / Area So, when area is doubled, pressure becomes half (b) the thrust is doubled keeping the area constant Ans : Pressure is directly proportional to thrust. So it gets doubled.
Q3 b) Give reason why potters place a large round piece of cloth on their heads when they carry heavy loads Ans : i) pressure is inversely proportional to contact area ii) round cloth increases the contact area thereby reducing the pressure. e) It is easier to burst an inflated balloon with a needle than with the finger Ans i) pressure is inversely proportional to contact area Ii)needle having lesser area of contact pricks the balloon with more pressure.
Q4. Two rods A and B of the same weight and equal length have different thickness. A boy held them vertically on sand as shown in the figure. Which one will sink less and why ? Ans: i) Pressure is inversely proportional to the area of contact. ii) Since rod B has more area , it will exert less pressure on the sand and will sink less.
