??? ??? ??? Science is a body of knowledge that goes back to D. Humankind's beginnings ??? ??? ??? The average speed of a horse that gallops a distance of 10 km in a time of 30 min is B. 20 km/h ??? ??? ??? An apple weighs 1 N. The magnitude of net force on the apple when it is in free-fall is C. 1N ??? ??? ??? If a freely falling object were somehow equipped with a speedometer on a planet where t