Home
Class 12
PHYSICS
Consider a system of two vectors overs...

Consider a system of two vectors
`overset(rarr)a=3hat i +4 hat j, overset(rarr)b=hat i+hatj` ,

A

`overset(rarr)r=sqrt(2)overset(rarr)a+5overset(rarr)b` will be making equal angles with and `overset(rarr)a` and `overset(rarr)b`

B

The angle made by `overset(rarr)r=overset(rarr)a+overset(rarr)b` with `overset(rarr)a` will be smaller as compared to angle made by with `overset(rarr)r` with `overset(rarr)b`

C

Angle made by `overset(rarr)r=overset(rarr)a+overset(rarr)b` with be greater as compared to angle made by with `overset(rarr)b`

D

Incomplete information to predict any of the above options

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we will analyze the two vectors given and check the options provided. We will focus on the first option as described in the video transcript. ### Step-by-Step Solution: 1. **Define the Vectors**: - Let \(\vec{a} = 3\hat{i} + 4\hat{j}\) - Let \(\vec{b} = \hat{i} + \hat{j}\) 2. **Calculate the Resultant Vector**: - According to the first option, the resultant vector \(\vec{r}\) is given by: \[ \vec{r} = \sqrt{2} \vec{a} + 5 \vec{b} \] - Substitute the values of \(\vec{a}\) and \(\vec{b}\): \[ \vec{r} = \sqrt{2}(3\hat{i} + 4\hat{j}) + 5(\hat{i} + \hat{j}) \] - This simplifies to: \[ \vec{r} = 3\sqrt{2}\hat{i} + 4\sqrt{2}\hat{j} + 5\hat{i} + 5\hat{j} \] - Combine the components: \[ \vec{r} = (3\sqrt{2} + 5)\hat{i} + (4\sqrt{2} + 5)\hat{j} \] 3. **Calculate the Magnitudes**: - The magnitude of vector \(\vec{a}\) is: \[ |\vec{a}| = \sqrt{3^2 + 4^2} = \sqrt{9 + 16} = 5 \] - The magnitude of vector \(\vec{b}\) is: \[ |\vec{b}| = \sqrt{1^2 + 1^2} = \sqrt{2} \] - The magnitude of vector \(\vec{r}\) is: \[ |\vec{r}| = \sqrt{(3\sqrt{2} + 5)^2 + (4\sqrt{2} + 5)^2} \] 4. **Calculate the Dot Products**: - For \(\cos \theta_1\) (angle between \(\vec{r}\) and \(\vec{a}\)): \[ \cos \theta_1 = \frac{\vec{r} \cdot \vec{a}}{|\vec{r}| |\vec{a}|} \] - Calculate \(\vec{r} \cdot \vec{a}\): \[ \vec{r} \cdot \vec{a} = (3\sqrt{2} + 5) \cdot 3 + (4\sqrt{2} + 5) \cdot 4 \] - For \(\cos \theta_2\) (angle between \(\vec{r}\) and \(\vec{b}\)): \[ \cos \theta_2 = \frac{\vec{r} \cdot \vec{b}}{|\vec{r}| |\vec{b}|} \] - Calculate \(\vec{r} \cdot \vec{b}\): \[ \vec{r} \cdot \vec{b} = (3\sqrt{2} + 5) + (4\sqrt{2} + 5) \] 5. **Compare the Angles**: - Since \(\cos \theta_1\) and \(\cos \theta_2\) are calculated, we can compare them to determine which angle is smaller. - If \(\cos \theta_1 > \cos \theta_2\), then \(\theta_1 < \theta_2\), meaning \(\vec{r}\) makes a smaller angle with \(\vec{a}\) than with \(\vec{b}\).

To solve the problem, we will analyze the two vectors given and check the options provided. We will focus on the first option as described in the video transcript. ### Step-by-Step Solution: 1. **Define the Vectors**: - Let \(\vec{a} = 3\hat{i} + 4\hat{j}\) - Let \(\vec{b} = \hat{i} + \hat{j}\) ...
Promotional Banner

Topper's Solved these Questions

  • INTRODUCTION TO VECTORS & FORCES

    VMC MODULES ENGLISH|Exercise JEE Main ( ARCHIVE ) ( LEVEL-1)|12 Videos
  • INTRODUCTION TO VECTORS & FORCES

    VMC MODULES ENGLISH|Exercise JEE Advanced ( ARCHIVE LEVEL-2)|12 Videos
  • INTRODUCTION TO VECTORS & FORCES

    VMC MODULES ENGLISH|Exercise level 1|75 Videos
  • GRAVITATION

    VMC MODULES ENGLISH|Exercise JEE Advance (Archive) TRUE/FALSE|1 Videos
  • JEE MAIN - 5

    VMC MODULES ENGLISH|Exercise PART I : PHYSICS (SECTION - 2)|5 Videos

Similar Questions

Explore conceptually related problems

The area of parallelogram represented by the vectors overset(rarr)A = 2 hat i + 3 hat j and overset(rarr)B=hat i+4 hat j is

What is the projection of vector overset(rarr)A=4hat I +3 hatj on vector overset(rarr)B=3hat I +4 hat j ?

Find unit vectors along overset(rarr)A=hat I + hat j - 2 hat k and overset(rarr)B=hat I +2 hat j -hat k

Dot product of two vectors overset(rarr)A and overset(rarr)B is defined as overset(rarr)A.overset(rarr)B=aB cos phi , where phi is angle between them when they are drawn with tails coinciding. For any two vectors . This means overset(rarr)A . overset(rarr)B=overset(rarr)B. overset(rarr)A that . The scalar product obeys the commutative law of multiplication, the order of the two vectors does not matter. The vector product of two vectors overset(rarr)A and overset(rarr)B also called the cross product, is denoted by overset(rarr)A xx overset(rarr)B . As the name suggests, the vector product is itself a vector. overset(rarr)C=overset(rarr)A xx overset(rarr)B then C=AB sin theta , overset(rarr)A=hat i+ hat j-hatk and overset(rarr)B=2 hat i +3 hat j +5 hat k angle between overset(rarr)A and overset(rarr)B is

Following forces start acting on a particle at rest at the origin of the co-ordinate system overset(rarr)F_(1)=-4 hat I -5 hat j +5hat k , overset(rarr)F_(2)=5hat I +8 hat j +6hat k , overset(rarr)F_(3)=-3hat I + 4 hat j - 7 hat k and overset(rarr)F_(4)=2hat i - 3 hat j - 2 hat k then the particle will move

Calculate the magnitude of the vector, overset(rarr)r =(3 hat i+4 hat j + 7hat k) metre.

Given vector overset(rarr)A=2 hat I +3hatj , the angle between overset(rarr)A and y-axis is :

(i) State the associative and commutative laws of vector addition. (ii) For two given vectors A=hat I + 2 hat j -3hat k , overset(rarr)B=2 hati -hat j + 3 hatk find the vector sum of overset(rarr)A and overset(rarr)B also find the magnitude of (overset(rarr)A+overset(rarr)B)

If overset(rarr)A=2 hat i + 3 hat j- hat k and overset(rarr)B=-hat i+3 hat j +4 hat k and then projection of overset(rarr)A on overset(rarr)B will be :

Find the volume of the parallelepiped whose edges are represented by the vectors overset(to) (a) = 2 hat(i) - 3 hat(j) -4 hat(k), overset(to)( b) = hat(i) + 2 hat(j) - hat(k) , overset(to)( c) =3 hat(i) - hat(j) - 2 hat(k) .

VMC MODULES ENGLISH-INTRODUCTION TO VECTORS & FORCES -level 2
  1. If overset(rarr)A=2 hat i + 3 hat j- hat k and overset(rarr)B=-hat i...

    Text Solution

    |

  2. A block of mass M is kept in elevator (lift) which starts moving upwar...

    Text Solution

    |

  3. Consider a system of two vectors overset(rarr)a=3hat i +4 hat j, ove...

    Text Solution

    |

  4. The angle between vector (overset(rarr)Axxoverset(rarr)B) and (overset...

    Text Solution

    |

  5. Dot product of two vectors overset(rarr)A and overset(rarr)B is defi...

    Text Solution

    |

  6. Dot product of two vectors overset(rarr)A and overset(rarr)B is defi...

    Text Solution

    |

  7. Dot product of two vectors overset(rarr)A and overset(rarr)B is defi...

    Text Solution

    |

  8. Maximum and minimum values of the resultant of two forces acting at a ...

    Text Solution

    |

  9. A force ( 3 hati +4 hat j) newton acts on a body and displaces it by...

    Text Solution

    |

  10. If a vector 2 hat (i) + 3 hat(j) + 8 hat(k) is perpendicular to the ve...

    Text Solution

    |

  11. What is the torque of a force overset(rarr)F=(2 hat i -3 hat j +4 hat ...

    Text Solution

    |

  12. The magnitudes of the X and Y components of overset(rarr)P are 7 and...

    Text Solution

    |

  13. A car is going in south with a speed of 5m//s. To a man sitting in car...

    Text Solution

    |

  14. The area of parallelogram represented by the vectors overset(rarr)A =...

    Text Solution

    |

  15. The river 500 m wide is flowing with a current of 4kph. A boat starts ...

    Text Solution

    |

  16. An aeroplane takes off from Mumbai to Delhi with velocity 50 kph at an...

    Text Solution

    |

  17. If the system is in equilibrum, find the Normal Reaction between 2kg a...

    Text Solution

    |

  18. The string and the pulley are massless and the system is in equilibriu...

    Text Solution

    |

  19. The block is always at rest, the maximum force which can be applied fo...

    Text Solution

    |

  20. A force of 200N is applied as shown in the figure on block of 3 kg. Th...

    Text Solution

    |