Physics-DPP-4-Kinematics
PHYSICS Topic: KINEMATICS Date:
1. Which of the following is a scalar quantity?
(a) Work (b) Displacement (c) Velocity (d) Acceleration
2. Which of the following operations make no sense in case of scalars and vectors?
(a) Multiplying any vector by a scalar (b) Adding a component of vector to the same vector
(c) Multiplying any two scalars (d) Adding a scalar to a vector of the same dimensions.
3. The minimum number of coplanar vectors of unequal magnitude required to produce a zero resultant is :
(a) 2 (b) 3 (c) 4 (d) more than 4
r r r r r r
4. The vectors A and B are such that A + B = A – B then the angle between the two vectors A and B will be
(a) 0o (b) 60o (c) 90o (d) 180o
ur ur ur
ur ur ur
ur ur
5. If A = B + C and the magnitudes of A, B and C are 5, 4 and 3 units respectively, the angle between A and C is :
(a)
cos–1 æç3ö÷
(b)
cos–1 æç4ö÷
π
(c)
(d)
sin–1 æç3ö÷
ç ÷ ç ÷ 2 ç ÷
è5ø
è5ø
è4ø
6. Two forces each numerically equal to 10 dynes are acting as shown in the following figure, then the resultant is :
(a) 10 dynes (b) 20 dynes (c) 10
dynes (d) 5 dynes
7. A particle is moving eastward with a velocity of 5 m/s. In 10 seconds, the velocity changes to 5 m/s northwards. The average acceleration in this time is :
(a) zero (b)
m/sec2 towards north-west (c)
m/sec2 towards north-east
(d) 1 m/sec2 towards north-west (e) 1 m/sec2 towards north.
2 2
r r r
8. Figure shows three vectors a, b and c , where R is the mid-point of PQ. Then which of the following relations is correct ?
(a)
r r r
a + b = 2 c
r r r
r r r
(b) a + b = c
r r r
(c)
a – b = 2c
(d) a – b = c
9. If a vector 2 ˆi + 3ˆj + 8kˆ is perpendicular to the vector 4 ˆj – 4 iˆ + αkˆ , then the value of α is :
1
(a) – 1 (b) 2
(c) – 1
2
(d) 1
10. If three vectors along co-ordinate axes represent the adjacent sides of a cube of length b, then the unit vector along its diagonal passing through the origin will be :
(a)
(b)
(c) ˆ ˆ ˆ
(d)
i + j + k
PHYSICS Topic: KINEMATICS Date:
Answer Key
1. (a) 2. (d) 3. (b) 4. (c) 5. (a)
6. (c)
7. (c)
8. (a)
9. (c)
10. (d)
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