3. Rebecca puts her backpack on a fan cart and turns the fan on. She then measures the speed each second afterward. At 10 seconds the cart has a speed of 20 cm per second. How fast will the cart be moving at 12 seconds?
O A 18 cm per second
OB 20 cm per second
OC.22 cm per secnod
01.24 cm per second

50 points please help :)

What two factors can affect the properties of a hydrocarbon? a. the number of its carbon atoms and the number of single bonds b. the number of its carbon atoms and the arrangement of its atoms c. the arrangement of its atoms and the number of its double bonds

8. how much enthalpy/heat is transferred when 0.5113gof ammonia (nh3) reacts with excess oxygen according| to the following equation: 4nh3 +502 - 4n0+ 6h20ah = -905.4j

Sandy is building a small toy car. he wants to use a balloon to power the toy car. he fills a balloon with air and then attaches a straw to the balloon. he tapes the balloon-straw combination to the car and then releases the end of the balloon. the toy moves forward as the air from the balloon comes out the back of the straw. what can sandy do to make the toy car move faster? a) use less air in the balloon. b) blow up the balloon more. c) use a longer straw. d) use larger tires.