In order to be considered a semi conductor the material must?
a. have insulator and conductor properties
b. resist electron flow
c. have ions that are negative and accept charges
d. easily accept electron flow

Christina can paint 420 square feet in 105 minutes. which unit rate describes the scenario?

What is the simplified form of square root of 400 to the 100th power ?

Aspacecraft can attain a stable orbit 300 kilometers above earth if it reaches a velocity of 7.7 kilometers per second. the formula for a rocket's maximum velocity v in kilometers per second is vequalsminus0.0098tplusc ln upper r, where t is the firing time in seconds, c is the velocity of the exhaust in kilometers per second, and r is the ratio of the mass of the rocket filled with fuel to the mass of the rocket without fuel. find the velocity of a spacecraft whose booster rocket has a mass ratio of 20, an exhaust velocity of 2.1 km/s, and a firing time of 15 s. can the spacecraft achieve a stable orbit 300 km above earth?