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

A particle with charge q = + 5e and mass m = 8.2*10-26 kg is injected horizontally with speed 1.1*106 m/s into the region between two parallel horizontal plates. The plates are 26 cm long and 1.1 cm apart.

A plane traveled south for 2.5 hrs at a velocity of 1200km/hr. What distance did it travel?

An incident ray of light strikes water at an angle of 30°. The index of refraction of air is 1.0003, and the index of refraction of water is 1.33. What is the angle of refraction rounded to the nearest whole number? 22° 24° 30° 42°

how much power is used if a force of 35 Newtons is used to push a box a distance of 10 meters in 5 seconds

The frequency of the second harmonic of a certain musical instrument is 100 Hz. What is the fundamental frequency of the instrument? 100 Hz 50 Hz 150 Hz 200 Hz

How does an electromagnetic wave propagate itself? a. A changing magnetic field induces an electric field perpendicular to the magnetic field. b. A changing electric field induces a magnetic field perpendicular to the electric field. c.

Which of the following is an example of convection? A. hot air rising and cooler air falling B. a hot object transferring heat to a cooler one C. a hot oven warming the air around it D. the rays of the Sun warming the earth

A 50,000 kg locomotive is traveling at 10 m/s when its engine and brakes both fail. How far will the locomotive roll before it comes to a stop? Assume the track is level.

A rectangular loop of wire with sides 0.262 and 0.401 m lies in a plane perpendicular to a constant magnetic field (see part a of the drawing). The magnetic field has a magnitude of 0.

In the system you're inspecting the damper motor isn't working, You decide to see if the damper-postion sensor us sending the proper signal to the which then signals the damper motor. A. heating coil B. duckwork c. energy source D. controller