If p=(2−2) and q=(34), find |q−12p|.
2√2
√13
5
√29
Correct answer is D
p=(2−2),q=(34)
12p=(1−1)
q−12p=(34)−(1−1)=(25)
|q−12p|=√22+52=√29
If n items are arranged two at a time, the number obtained is 20. Find the value of n.
5
10
15
40
Correct answer is A
nP2=n!(n−2)!=20
n(n−1)(n−2)!(n−2)!=20
n(n−1)=20⟹n2−n−20=0
n2−5n+4n−20=0
n(n−5)+4(n−5)=0
n=5 or -4
n=5
50 m
250 m
350 m
500 m
Correct answer is B
s=ut+12at2
u=0,t=10secs,a=5ms−2
s=0+125×102
s=250m
Express r = (12, 210°) in the form a i + b j.
6(-i + \sqrt{3} j)
6(-\sqrt{3} i - j)
6(i - \sqrt{3} j)
6(i + \sqrt{3} j)
Correct answer is B
F = F \cos \theta i + F \sin \theta j
r = (12, 210°) = 12 \cos 210 i + 12 \sin 210 j
= - 6\sqrt{3} i - 6j
= 6(-\sqrt{3} i - j)