A ball is projected with velocity 20 √3 m/s at an angle of 60° with the horizontal the time taken after which the velocity vector will make an angle of 30° with horizontal is??
Answers
Answer:
2 seconds
Explanation:
as initial vertical component will be 20√3 *Sin(60)=30m/s
initial horizontal component (which will remain same throughout its
journey) will be 20√3*Cos(60)=10√3 m/s
now
when velocity vector make an angle of 30 degrees with the hozontal
then also the horizontal component remains same as 10√3 m/s
so, suppose the magnitude of velocity vector V be x m/s
therefore x*Cos(30)=10√3 m/s
hence, magniutde of V is x=20m/s
therefor vertical vector will be 20*Sin(30) =10m/s
now according to equation "v=u=at"
time taken to decrease its velocity fron 30 m/s to 10m/s(while moving upward) will be given by
10=30+(-10)*t
-10t=-20
t=2s
Answer: 2 sec
Explanation:
