Question

Two seconds after projection a projectile is travelling in a direction inclined at 30o to the horizontal after one more sec, it is travelling horizontally, the magnitude and direction of its velocity are 

(a) 2√20 m/sec, 60°

(b) 20√3 m/sec, 60°

(c) 6 √40 m/sec, 30°

(d) 40√6 m/sec, 30°

Answer 1

Correct option (b) 20√3 m/sec, 60°   

Explanation:

Let in 2 sec body reaches upto point A and after one more sec upto point B. 

Total time of ascent for a body is given 3 sec i.e. 

Horizontal component of velocity remains always constant 

For vertical upward motion between point O and A