A wooden board hangs from a spring scale which measures 100 N when there is no wind. The board is oriented parallel with the ground below. The board has area = 2 m2 and has negligible thickness. When the air above the board moves at 4.9 m/s and the air below the board is stationary, the spring scale now read as:
a. 65N
b. 69N
c. 73N
d. 77N
e. 81N

Uranium has two naturally occurring isotopes. 238u has a natural abundance of 99.3% and 235u has an abundance of 0.7%. it is the rarer 235u that is needed for nuclear reactors. the isotopes are separated by forming uranium hexafluoride uf6, which is a gas, then allowing it to diffuse through a series of porous membranes. 235uf6 has a slightly larger rms speed than 238uf6 and diffuses slightly faster. many repetitions of this procedure gradually separate the two isotopes. what is the ratio of the rms speed of 235uf6 to that of 238uf6? express your answer to five significant figures.

Aforce of 8,480 n is applied to a cart to accelerate it at a rate of 26.5 m/s2. what is the mass of the cart? 865 kg 320 kg 12.1 kg 3.12 kg

Which of the following is the largest disadvantage of about half of the electricity in the united states comes from burning