The main reason for making the cover of a vacuum

flask airtight is to prevent heat loss by

A. conduction

B. evaporation

C. radiation

D. convection

A water balloon dropped from a window high above the ground falls y = 4.9t2 m in t sec. find the balloon's (a) average speed during the first 3 sec of fall. (b) speed at the instant t = 3.

A light-year is: the distance traveled by light in one year the distance from earth to the sun equal to 93,000,000 miles the time required for light to travel in one year

1. Assume it takes 7.00 min to fill a 30.0-gal gasoline tank. a. calculate the rate at which the tank is filled in gallons per second? b. calculate the rate at which the tank is filled in cubic meters per second? C.

Identify three possible components of a dna nucleotide.

Paula is studying two different animals. Both animals are classified within the same genus, but they are different species. Based on this, it can be determined that the animals

What is energy? (Not the answer from google search.)

Explain why the friction force between two surfaces increases if the force is pushing the surfaces together increases.

As energy moves in waves through the water, the water moves a. in waves toward shore. c. in the direction of the waves. b. in a small circular movement. d. against the current.

Which of the following values represents an index of refraction of an actual material? A. 0 B. 1 / 4 C. 5 / 4 D. 1 / 2

Which statement best describes the effect of scientific advances on society? A. They always have a positive impact on society. B. They are inspired by the needs of society. C. they do not affect society beyond the community level. D.