From the top of a tower of height 40 m, a ball is projected upwards with a speed of 20 ms–1 at an angle of 30o to the horizontal. If g = 10 ms–2, after how long will the ball hit the ground?


Correct option is



The horizontal range R = AC is   




At C, the velocity of the ball is again 20 ms–1 directed down 

The downward vertical component of this velocity is 20 sin 30o = 10 ms–1. The ball ill hit the ground at D after travelling a vertical distance h = 40 m. If t1 is the time taken for this, then  




The positive root of this quadratic equation is t1 = 2s. Now, the time of flight from to C via D is 




 Total time taken




Four projectiles are projected with the same speed at angles 20o, 35o, 60oand 75o with the horizontal. The range will be the longest for the projectile whose angle of projection is


A player throws a ball which reaches the other player in 4 seconds. If the height of each player is 1.8 m, what is the maximum height attained by the ball above the ground?


A projectile thrown at an angle of 30o with the horizontal has a range R1and attains a maximum height h1. Another projectile thrown, with the same velocity, at an angle 30o with the vertical, has a range R2 and attains a maximum height h2. The relation between R1 and R2 is


A projectile attains a certain maximum height when projected from earth. If it is projected at the same angle and with the same initial speed from the moon, where the acceleration due to gravity is one-sixth that on earth, by what factor will the maximum height of the projectile increase?



A body is projected horizontally from the top of a building 19.6 m high. How long will it take to hit the ground?

Given g = 9.8 ms–2.