A body is projected with an initial speed of 100 sqrt(3) ms^(-1) at an angle of 60^(@) above the horizontal. If g = 10ms^(-2) then velocity of the projectile (a) Is perpendicular to it's acceleration at the instant t = 15 sec. (b) Is perpendicular to initial velocity of projection at t = 20 sec. (c) Is minimum at the highest point (d) Changes both in magnitude and direction, during its flight. Mark the answer as.

A body is projected with an initial speed of 100 sqrt(3) ms^(-1) at an

1.	A body is projected with an initial speed of 100 sqrt(3) ms^(-1) at an angle of 60^(@) above the horizontal. If g = 10ms^(-2) then velocity of the projectile (a) Is perpendicular to it's acceleration at the instant t = 15 sec. (b) Is perpendicular to initial velocity of projection at t = 20 sec. (c) Is minimum at the highest point (d) Changes both in magnitude and direction, during its flight. Mark the answer as.
Answer» If a, B, C and d are correct If a, c and d are correct If b, c and d are correct If a, b and d are correct Answer :A