The ability to pick up small objects, to stack objects, and to carry objects appears first during which time period?
a. after two years
b. six to twelve months
c. birth to six months
d. twelve to eighteen months

A500g object falls off a cliff and losers 100 j from its gravitational potential energy store. if the gravitational field strength g=9.8n/kg, how high is the cliff?

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •  

What does every magnet possess? a. iron metal b.strong magnetic field c.repulsion d.north and south poles