Why is most space exploration accomplished with spacecraft that do not have astronauts on board

When a surface vibrates, air is forced to move, creating a sound wave. What kind of force is exerted by the moving surface on the air?

Force is vector or scalar

You ride your bicycle into the country side on a bike path. You travel 6 kilometers the first hour, 3 kilometers the second hour, 6 the third what is your average speed?

Temperature of 273K is the temperature at which water

Which scenario describes a change in velocity? A. A skydiver that has reached terminal velocity (a constant speed) while falling. B. A ride that spins clockwise and then counterclockwise. C. A car traveling east at 55 km/hr. D.

A man consumes 2245 kcal of food in one day, converting most of it to maintain body temperature. If he loses half this energy by evaporating water (through breathing and sweating), how many kilograms of water evaporate?

If an eagle and a bumblebee are traveling at 8km/hr which has more momentum?

For each case, identify the force (including its direction) that causes the acceleration. (a) A sprinter at the very start of the race.

Select the effects of radiation below that are stochastic: associated with short-term, high-level exposure associated with long-term, low-level exposure include cancer and other DNA mutation include burns and radiation sickness

On the modern periodic table, elements are ordered according to what?