physics-class-11-unit-05-chapter-01-forces-on-bodies-contact-and-non-contact-forces-lecture-1-8-k7q9guxs-hw

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Newton's Third Law </primary>
<hr>
<main>

* If there are two bodies, body A and B, then the body A exerts a force $F_{B A}$ on body $B$ then the body $B$ exerts a force $F_{A B}$ on  an body $A$.
* Where $F_{A B}=-F_{B A}$
* If force acting on the book:force due to earth on the book, refer as the weight
* Table exerts a force on book $=F_{B T}$

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px"> $\rightarrow$ Forces on Bodies Contact and Non-Contact Forces $\rightarrow$ <span style = "color:blue"> Newton's Third Law </span> $\rightarrow$ Newton's Third Law $\rightarrow$ Newton's Third Law </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Newton's Third Law </primary>
<hr>
<main>

- $F_{B E}$ and $F_{B T}$ cancel each other $\rightarrow$ Book is at rest.

- $F_{B E}$ and $F_{B T}$ do NOT constitute an action reaction pair.

- Both $F_{B E}$ and $F_{B T}$ act on the same body $\rightarrow$ book.

</div>

![image](https://temp-public-img-folder.s3.ap-south-1.amazonaws.com/sathee.prutor.images/subject-images/iitpal/image/physics-class-11-unit-05-chapter-01-forces-on-bodies-contact-and-non-contact-forces-lecture-1_8-k7q9guxs_hw-059-0310.8.jpg)

</div>

</main>
<hr>
<footer style = "font-size: 18px">Forces on Bodies Contact and Non-Contact Forces $\rightarrow$ Newton's Third Law $\rightarrow$ <span style = "color:blue"> Newton's Third Law </span> $\rightarrow$ Newton's Third Law $\rightarrow$ Types of Forces </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Newton's Third Law </primary>
<hr>
<main>

- Action and Reaction on pair are on 2 different bodies.

- $F_{B E} \rightarrow$ Force on book by earth.

- Reaction to $F_{B E}$ is $F_{E B}$ the force on earth by book.

- $F_{BT} \rightarrow$ Force On book by table.

</div>
	
<div style='float: right; width:0%;'>
		
![image](https://temp-public-img-folder.s3.ap-south-1.amazonaws.com/sathee.prutor.images/subject-images/iitpal/image/physics-class-11-unit-05-chapter-01-forces-on-bodies-contact-and-non-contact-forces-lecture-1_8-k7q9guxs_hw-092-0480.0.jpg)

</div>

</main>
<hr>
<footer style = "font-size: 18px">Newton's Third Law $\rightarrow$ Newton's Third Law $\rightarrow$ <span style = "color:blue"> Newton's Third Law </span> $\rightarrow$ Types of Forces $\rightarrow$ Gravitational Force </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Gravitational Force </primary>
<hr>
<main>

* Force due to gravity 
* Newton's law of universal gravitation
* The force on the body A due to body B is $F_{A B}=\frac{G m_1 m_2}{r^2}$ (direction is from A to B)

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Newton's Third Law $\rightarrow$ Types of Forces $\rightarrow$ <span style = "color:blue"> Gravitational Force </span> $\rightarrow$ Gravitational Force $\rightarrow$ Gravitational Force </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Gravitational Force </primary>
<hr>
<main>

- Universal gravitation constant: $G=6.67 \times 10^{-11} \mathrm{N} \frac{\mathrm{m}^2}{\mathrm{kg}^2}$

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Types of Forces $\rightarrow$ Gravitational Force $\rightarrow$ <span style = "color:blue"> Gravitational Force </span> $\rightarrow$ Gravitational Force $\rightarrow$ Gravitational Force </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Gravitational Force </primary>
<hr>
<main>

- Any body which is on surface of earth or close to the surface will experience a gravitational force due to earth

* $ m$ =  mass of earth
* $ R_e$ = radius of earth

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Gravitational Force $\rightarrow$ Gravitational Force $\rightarrow$ <span style = "color:blue"> Gravitational Force </span> $\rightarrow$ Gravitational Force $\rightarrow$ Gravitational Force </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Gravitational Force </primary>
<hr>
<main>

- $F_{b e}=\frac{G m_b M}{r^2}$

- If body on surface of earth,  r=$R_e$

- $R_e =6370 \mathrm{km} =6.37 \times 10^6 \mathrm{m} $

- $F_{b_e}  =\frac{G M}{R_e^2} \cdot{m_b}$

- $\frac{G M}{R_e^2}$ = g

- g is called the gravitational constant.

</div>
	
<div style='float: right; width:0%;'>

</div>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Electromagnetic Force </primary>
<hr>
<main>

- $F=\frac{q}{C} (\vec{v} \times \vec{B})$

- Where:

- $\vec{v} \rightarrow$ Velocity

- $\vec{B} \rightarrow$ Magnetic field intensity

- Three basic forces which act from a distance gravity, electrostatic forces and electromagnetic forces.

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Gravitational Force $\rightarrow$ Electrostatic Force $\rightarrow$ <span style = "color:blue"> Electromagnetic Force </span> $\rightarrow$ Contact Force $\rightarrow$ Contact Forces </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Contact Force </primary>
<hr>
<main>

- Block exerts a force on Table. 
- Table exerts on equal and opposite force on block.

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Electrostatic Force $\rightarrow$ Electromagnetic Force $\rightarrow$ <span style = "color:blue"> Contact Force </span> $\rightarrow$ Contact Forces $\rightarrow$ Contact Forces </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Contact Forces </primary>
<hr>
<main>

* Force is in a general direction 
| $F_{AB}$ | $F_{BA}$ |
| -------- | -------- |

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Electromagnetic Force $\rightarrow$ Contact Force $\rightarrow$ <span style = "color:blue"> Contact Forces </span> $\rightarrow$ Contact Forces $\rightarrow$ Contact Forces </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Contact Forces </primary>
<hr>
<main>

* Normal component which is in a direction which is normal to the contact
* The other force is called  as the tangential component
* The contact force between bodies A and B will be divided into two parts a normal component which is perpendicular to the two areas and a tangential component which is in the tangential direction

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Contact Force $\rightarrow$ Contact Forces $\rightarrow$ <span style = "color:blue"> Contact Forces </span> $\rightarrow$ Contact Forces $\rightarrow$ Contact Forces </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Contact Forces </primary>
<hr>
<main>

* When the bodies have to be in contact the relative motion between A and B has to be only along the tangential direction
* If we have a contact force between two bodies A and B it acts in a general direction we divided into two components

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Contact Forces $\rightarrow$ Contact Forces $\rightarrow$ <span style = "color:blue"> Contact Forces </span> $\rightarrow$ Contact Forces $\rightarrow$ Contact Forces </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Contact Forces </primary>
<hr>
<main>

* The component which is normal to the surface: N (normal reaction)
* Perpendicular to the contact: normal reaction
* The second component will be the tangential component

</div>

</div>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Contact Forces </primary>
<hr>
<main>

<div style='float: left; width:100%; text-align: left; font-size:30px;'>
 
* Tangential component of contact force: force of friction
* Force of friction could exist even if the body is in contact with air or with water
* Tangential component which will be a component called the frictional force due to air or water
* We could have contact between a solid and a liquid or a gas
* Case: when we have when both the contacting bodies are solids
* Friction is a contact force
* Friction is in the tangential direction

</div>

</div>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Kinematics </primary>
<hr>
<main>

- We have a body A and body B.

- Let the velocity of body $A$ is $v_A$ and the velocity of body $B$ is $v_B$.

- Both are the tangential components of the velocities.

- "t" shows that it is a tangential component.

- The two bodies are not slipping with respect to each other.

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Contact Forces $\rightarrow$ Contact Forces $\rightarrow$ <span style = "color:blue"> Kinematics </span> $\rightarrow$ Kinematics $\rightarrow$ Impending Slip </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Coulombs Law of Friction </primary>
<hr>
<main>

- **Example:** Duster is kept on the block

* Tangential force it will try to stop the relative motion
* When no other force is being applied on this duster, it has two forces, weight of the duster and the contact force which will have two components a normal reaction and a friction

</div>
	
<div style='float: right; width:50%;max-width:450px;'>
<img src="https://imagedelivery.net/YfdZ0yYuJi8R0IouXWrMsA/2fb39a13-fdff-46b6-ac65-58b8c59d5f00/public" width="30%">

</div>

</main>
<hr>
<footer style = "font-size: 18px">Impending Slip $\rightarrow$ Coulombs Law of Friction $\rightarrow$ <span style = "color:blue"> Coulombs Law of Friction </span> $\rightarrow$ Coulombs Law of Friction $\rightarrow$ Impending Slip </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Coulombs Law of Friction </primary>
<hr>
<main>

- When we apply a small force the body does not move that means the friction force is  automatically acting on the tangential surface which opposes the motion.

- Frictional force is a self adjusting force and it tries to oppose the motion.

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Coulombs Law of Friction $\rightarrow$ Coulombs Law of Friction $\rightarrow$ <span style = "color:blue"> Coulombs Law of Friction </span> $\rightarrow$ Impending Slip $\rightarrow$ Impending Slip </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Impending Slip </primary>
<hr>
<main>

* As F increases reach a stage where duster is about to move, at this stage we have the state of impending slip.
* Coulomb's laws say that, when we have impending slip that means the body is just about to move then the force of friction is equal to a constant = $\mu_s \times N$

- **Where N is the normal force or normal reaction on the body**

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Coulombs Law of Friction $\rightarrow$ Coulombs Law of Friction $\rightarrow$ <span style = "color:blue"> Impending Slip </span> $\rightarrow$ Impending Slip $\rightarrow$ Impending Slip </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Impending Slip </primary>
<hr>
<main>

* Duster starts to move, accelaration in $\leftarrow$
* Case of impending slip, friction is directly proportional to the normal reaction

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Coulombs Law of Friction $\rightarrow$ Impending Slip $\rightarrow$ <span style = "color:blue"> Impending Slip </span> $\rightarrow$ Impending Slip $\rightarrow$ Impending Slip </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Impending Slip </primary>
<hr>
<main>

* The maximum value of friction force till we start to have slip will be $\mu_s N$.
* For impending slip 
* $f=\mu_s N$

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Impending Slip $\rightarrow$ Impending Slip $\rightarrow$ <span style = "color:blue"> Impending Slip </span> $\rightarrow$ Impending Slip $\rightarrow$ Impending Slip </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Impending Slip </primary>
<hr>
<main>

* slip $\rightarrow f=\mu_k N$
* $\mu_k \rightarrow $ coeficient of kinetic friction
* N $\rightarrow$ Normal reaction
* Generally, $\mu_k<\mu_s$
* $\mu_k, \mu_s \rightarrow$ independent of relative velocity of bodies in contact
* Depend on surfaces of contact

</div>

</div>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Impending Slip </primary>
<hr>
<main>

- Translation: where the entire block moves with the same velocity.

</div>

</div>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Impending Slip </primary>
<hr>
<main>

- It is possible that the normal reaction does not act at the center, but it acts at some other point somewhere in the contact zone of the body.

</div>

</div>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Impending Slip </primary>
<hr>
<main>

- Directions of friction $\rightarrow$ oppose relative slip on body in question
|Force|Formula|Condition|
| -------- | -------- | -------- |
| friction    | < $\mu_s N$    |no slip     |
|     | =$\mu_s N$     | impending slip     |
|     | =$\mu_k N$     | slip     |

</div>

</div>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Problem </primary>
<hr>
<main>

* A block is moving with a speed of 5 m/s is on ground and the ground is at rest
* Let us say point A is on the block point B is on the ground

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Impending Slip $\rightarrow$ Impending Slip $\rightarrow$ <span style = "color:blue"> Problem </span> $\rightarrow$ Impending Slip $\rightarrow$ Impending Slip </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Impending Slip </primary>
<hr>
<main>

- $ v_A$=5 $\hat{i} $

- $ v_B$=0 $\hat{i} $

- Velocity of A with respect to B = $v_A-v_B$=5$ \hat{i}$

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Impending Slip $\rightarrow$ Problem $\rightarrow$ <span style = "color:blue"> Impending Slip </span> $\rightarrow$ Impending Slip $\rightarrow$ Impending Slip </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Impending Slip </primary>
<hr>
<main>

- $a_A=2 {m}/{s^2}  \hat{i}$

- $a_B=2 {m}/{s^2}  \hat{i}$

- $ \vec{v}_{A / B}=5-5=0 $

- $ \vec{a}_{A B}=2-2=0$

- <span style="color:blue">No slip</span>

</div>

</div>

</main>
<hr>
<footer style = "font-size: 18px">Problem $\rightarrow$ Impending Slip $\rightarrow$ <span style = "color:blue"> Impending Slip </span> $\rightarrow$ Impending Slip $\rightarrow$ Thank You </footer>

### <Success style="font-size:25px"> Forces On Bodies Contact And Non Contact Forces L-1 </Success>
### <primary style="font-size:24px"> Impending Slip </primary>
<hr>
<main>

- Slip: $\vec{v}_A=\vec{V}_B$, not slipping.

- $\overrightarrow{a_A}-\overrightarrow{a_B}=a_{A / B}=(2-3) \hat{i} = -\hat{i}$

- Friction force on body $\rightarrow \hat{i}$.

</div>

</div>