an object is shot vertically upward into the air with an initial velocity of 20 m/s? which of the following correctly describes the velocity and acceleration of the object after 4seconds?

Select all the correct answers. which changes will increase the rate of reaction during combustion? decreasing the area of contact between the reactants adding more oxygen to the reaction removing heat from the reaction changing the reactants from solid form to powdered form lowering the exposure of the reactants to air