#### Kinematics Important Questions

11th Standard

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Physics

Time : 01:00:00 Hrs
Total Marks : 50
10 x 1 = 10
1. Identify the unit vector in the following

(a)

$\hat { i } +\hat { j }$

(b)

$\frac { \hat { i } }{ \sqrt { 2 } }$

(c)

$\hat { k } -\frac { \hat { j } }{ \sqrt { 2 } }$

(d)

$\frac { \hat { i } +\hat { j } }{ \sqrt { 2 } }$

2. If a particle has negative velocity and negative acceleration, its speed

(a)

increases

(b)

decreases

(c)

remains same

(d)

zero

3. If the velocity is $\overrightarrow { v } =2\hat { i } +{ t }^{ 2 }\hat { j } -9\overrightarrow { k }$ then the magnitude of acceleration at t=0.5 s is

(a)

1 ms-2

(b)

2 ms-2

(c)

zero

(d)

-1 ms-2

4. If an object is dropped from the top of a building and it reaches the ground at t = 4 s, then the height of the building is (ignoring air resistance) (g = 9.8 ms-2)

(a)

77.3 m

(b)

78.4 m

(c)

80.5 m

(d)

79.2 m

5. Which one of the following satatement is true?

(a)

A scalar quantity is conserved in a process

(b)

A scalar quantity does not vary from one point to another in apace

(c)

A scalar quantity can never take -ve values

(d)

A scalar quantity has only magnitude and no direction.

6. The angle between A i +j and B = i - j is

(a)

45°

(b)

90°

(c)

-45°

(d)

180°

7. The component of position vector $\overrightarrow { r }$ along x-axis will maximum value if

(a)

$\overrightarrow { r }$ is along the x - axis

(b)

$\overrightarrow { r }$ makes an angle of 45° with x - axis

(c)

$\overrightarrow { r }$  is along the y - axis

(d)

$\overrightarrow { r }$  is along - ve y - axis

8. Consider the quantities pressure, power, energy, impulse, charge. Out of these, the only vector quantity is

(a)

pressure

(b)

power

(c)

impulse

(d)

charge

9. The length of a vector is _______________

(a)

always a negative quantity

(b)

always a positive quantity

(c)

either positive or negative

(d)

denoted by '$\lambda$

10. Distance is a scalar quantity and ______________ is a vector.

(a)

Speed

(b)

Length

(c)

Time

(d)

Displacement

11. 6 x 2 = 12
12. Explain what is meant by Cartesian coordinate system?

13. Define a vector. Give examples.

14. Define a scalar. Give examples

15. What is Kinematics?

16. What is meant by frame of reference?

17. What is right handed coordinate system?

18. 6 x 3 = 18
19. How do you deduce that two vectors are perpendicular?

20. Define displacement and distance.

21. Define velocity and speed

22. What is meant by point mass and give suitable example?

23. What do you mean by motion in one, two and three dimensions?

24. What are the different types of vectors?

25. 2 x 5 = 10
26. Two vectors $\vec A$ and $\vec B$ of magnitude 5 units and 7 units respectively make an angle 60° with each other as shown below. Find the magnitude of the resultant vector and its direction with respect to 7 unit the vector $\vec A$.

27. Derive the relation between Tangential acceleration and angular acceleration.