Question: Just after the gun a sprinter of mass 65kg is pushing against the starting block with a force of 800N. The force acts at an angle of 65 degrees to the horizontal. Calculate: - the resultant horizontal force acting on her - the resultant vertical force acting on her - the forward acceleration of her centre of gravity - the upward acceleration of her centre of gravity My attempt: I'm guessing the resultant horizontal force is 0, as the starting block would exert an equal force on the runner? Then resultant vertical force would be mass x gravity (65 x 9.8 = 637N). But I don't know how to attempt the other two questions??