George is planning an experiment to see how fast different sized cans of soup can roll down a ramp in his kitchen. He will be rolling them down a ramp and them time how fast it take them to travel 1 meter after the ramp. George writes the following procedure to conduct his experiment. Gather three different sized soup cans, a 30 cm ramp, a timer, a meterstick, and a scale.
Weigh the first can and record the size
Put the meterstick at the end of the ramp
Roll the soup can down the ramp, time how long it takes to move along the meterstick
Calculate the velocity
Repeat steps 2-5 for the other cans.
Which of the following should George add in order to improve his procedure?

a
Record the velocity of every can
b
Find different objects other than cans to work with
c
Change the Height of the ramp to make the cans go faster
d
Mention that he needs to clean up his materials

What would the difference of spectral lines emitted by hydrogen gas in distant galaxies which is normally found at a wavelength of 21 cm on earth, be observed at 21.1 centimeters?

In a voltaic cell, electrons flow from the (positive/negative) to the (positive/negative) terminal.

Clothing made of several thin layers of fabric with trapped air in between, often called ski clothing, is commonly used in cold climates because it is light, fashionable, and a very effective thermal insulator. so it is no surprise that such clothing has largely replaced thickand heavy old-fashioned coats. (a) consider a jacket made of five layers of 0.1-mm-thick synthetic fabric (k = 0.13 w/m·°c) with 1.5-mm-thick air space (k = 0.026 w/m·°c) between the layers. assuming the inner surface temperature of the jacket to be 28°c and the surface area to be 1.25 m2, determine the rate of heat loss through the jacket when the temperature of the outdoors is 0°c and the heat transfer coefficient at the outer surface is 25 w/m2·°c. (b) what would your response be if the jacket is made of a single layer of 0.5-mm-thick synthetic fabric? what should be the thickness of a wool fabric (k = 0.035 w/m·°c) if the person is to achieve the same level of thermal comfort wearing a thick wool coat instead of a five-layer ski jacket?