Which if the following statements is true? a. instantaneous acceleration is always changing. b. an object at rest has an instantaneous acceleration of zero. c. an object that is accelerating is always changing direction. d. an object that is accelerating is always changing speed.

Gravity is pulling an object into the sun. the closer the object gets to the sun, the greater the gravitational force that acts on the object, increasing its acceleration. a line graph plotting the speed of the object against time would have which shape? a: straight line of positive slope b: curved line that slopes upward c: curved line that slopes downward d: straight line of negative slope