Draw a labelled diagram.
Find the value of secθ.
→r1=30^j
→r2=3t^i
→r3=12[(0.4)sinθ^i+(0.4)cosθ^j]t2
For collision,
→r1+→r2=→r3
⇒(30)^j+(3t)^i=0.2t2[sinθ^i+cosθ^j]
⇒30=0.2t2cosθ and 3t=0.2t2sinθ
⇒150=t2cosθ and 15=tsinθ
Dividing both the equations,
⇒150225=cosθsin2θ⇒23=cosθ(1−cos2θ)
⇒cosθ=12
secθ=2
Final Answer: (2)