39) A stone is thrown vertically upwards with a vertical velocity of 49 m/sec. It returns to the ground in

40) A projectile has maximum range of 40 m on a horizontal plane. If angle of projection is a and the time of flight is 1 second, then sin a must be about

41) If the direction of projection bisects the angle between the vertical and the inclined plane, then the range of projectile on the inclined plane is

42) If a projectile is fired with an initial velocity of 10 m/sec at an angle of 60° to the horizontal, its horizontal and vertical velocity at the highest point of trajectory are

43) The angle of projection at which the horizontal range and maximum height of a projectile are equal to