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

44) A stone is thrown up a slope of inclination 60° to the horizontal. At what angle to the slope must the stone be thrown so as to land as far as possible from the point of projection