1. which of the following is not part of john dalton's atomic theory?

a. all elements are composed of atoms.
b. all atoms of the same element have the same mass.
c. atoms contain subatomic particles.
d. a compound contains atoms of more more than one element.

2. who provided evidence for the existence of a nucleus in an atom?

a. john dalton
b. j. j thomson
c. democritus
d. ernest rutherford

An insurance company wants to know if the average speed at which men drive cars is higher than that of women drivers. the company took a random sample of 27 cars driven by men on a highway and found the mean speed to be 72 miles per hour with a standard deviation of 2.2 miles per hour. another sample of 18 cars driven by women on the same highway gave a mean speed of 68 miles per hour with a standard deviation of 2.5 miles per hour. assume that the speeds at which all men and all women drive cars on this highway are both approximately normally distributed with unknown and unequal population standard deviations.

Iwill give 30 points to whoever answers ! what is the formula for actual mechanical advantage and ideal mechanical advantage?

Diego is trying to lift a piano to the second floor of his house. diego uses a pulley system and gives a big lift to the piano. the piano moves upward, then stops, and then it starts to fall to the ground. which list best describes the forces on the piano in the proper order? positive force → balanced force → negative force negative force → balanced force → positive force positive force → unbalanced force → negative force negative force → unbalanced force → positive force