Question

An object is thrown up with a speed of 50m/s. Its height from the ground after 7s is

Answer 1

s=ut+1/2(at^2)
s=50*7 + (1\2)(-10*49)   (acceleartion due to gravity is in opposite direction to                                            displacement .thus a is -ve) 
s=350-5*49
s=350-245
s=105 m