Question

1. Let u = (1 + i + k)m/s and a=(21+3 +4k)m/s. The velocity of the body at the end of 3 seconds is

a) (41+5j +6k)m/s
b) (31+4, +5k)m/s [ ]
c)(7i+ 10j + 13 k)m/s
d) Zero

2.The momentum of a body of mass 8 kg moving with a speed of (21+ 4j -- k) m/s is

a) (16i + 32j - 8k) kg ms'
b) (161 - 32 j + 8k) kg ms' [ ]
c) (-16i + 32 j +8k) kg ms!
d) All the above

3. If (21 +3j + xk) and (14i +213+ 7k) are parallel, the value of x is
a) 1
b) 7 [ ]
c) 0
d) - 1

4. The position of a particle at two instants is (3,2,5) and (4,3,8) the displacement vector is
a) (31 + 2% + 5k)
b) (4i + 3j + 8k) [ ]
c)(-i- j - 3k)
d) (i + i + 3k)

5. A force of (2i+j+ k) acts on a body which is initialy at rest. At the end of 20 seconds the
velocity of the body is (4i +2j + 2k) m/s. Its mass is

a) 10 g
b) 20 g [ ]
c) 30 kg
d) 40 kg

6. A body of mass 4 kg moves under a force of 8i + 16 j +20k, then the acceleration vector is (in m/2)
a) (i+j+k)
b) (21 +4j + 5k) [ ]
c) (i + 2k)
d) ( + 4k)

7. If a = kb, then a and ū are antiparallel to each other if

a) K = 0
b) K< 0 [ ]
c) K> 0
d) None of these

8. If p=kg such that p is momentum and q is velocity, then k is

a) time
b) distance [ ]
c) mass
d) density

9. Given a = xū such that a is force vector and is change in momentum vector, then the units of
a) m
b) m/s [ ]
c) s
d)s

10. If a is a vector such that b = 3a, then the length of the vector b is [ ]

a) equal to that of a
b) equal to 3 times the length od a
c) equal to √3 times the length of a
d) equal to
1\√3 times the length of a
​

Answer 1

Explanation:

2.The momentum of a body of mass 8 kg moving with a speed of (2i+ 4j -k) m/s is

a) (16i + 32j - 8k) kg ms'

b) (161 - 32 j + 8k) kg ms' [ ]

c) (-16i + 32 j +8k) kg ms!

d) All the above

8x(2i+4j-k)

(16i+32j-8k)kgms