A projectile is thrown with initial velocity `u_(0)` and angle `30^(@)` with the horizontal. If it remains in the air for 1s. What was its initial velocity ?

Options

A. 19.6 m/s
B. 9.8 m/s
C. 4.9 m/s
D. 1 m/s

Answer

B

Explanation

Time of flight , `T = (2u sin theta)/g`
Here `u = v_(0) , theta = 30^(@) , T = 1 s`
`:. T = (2v_0 sin30^@ )/g " or " v_0 =(gT)/(2 sin 30^@)`
`v_0 =(9.8xx1)/(2xxsin30^@) = (9.8xx1)/(2xx(1//2))=9.8 ` m//s