C. is correct. when you make a pizza, you see the the meat or pepperoni or cheese heating up and sometimes melted. (thats physical). on the inside the crust in heated and the toppings are cooked (chemical)
The half life is 30 minutes.
30 mins- 1/2 left
60 mins- 1/4 left
90 mins- 1/8 left
120 mins- 1/16 left
120 mins= 2 hours
Speed is the distance travelled by an object whereas velocity is distance travelled by an object per unit time in a given direction.
Answer:
D. I'm guessing
The gold-foil experiment showed that the atom consists of a small, massive, positively charged nucleus with the negatively charged electrons being at a great distance from the centre.
