7. In which of the following conditions would a person not hear an echo? A. A sound wave reaches the ear, and the reflected wave reaches the ear less than 0.1 seconds later. B. A person is standing in the range of the sound waves coming from the original sound source as well as the reflected waves. C. A person is standing 30 meters in front of the reflecting surface. D. The reflecting source is approximately 21.5 meters from the person. Mark for review (Will be highlighted on the review page)

A gravitational field surrounds anything that has __ A density B electricity C velocity D mass

You would have the largest mass of gold if it weighed 1 N on the Moon Earth both the same on the Earth the mass will be double

How many significant figures are in this length? .002500 dm $\square $

Use the formula $F=G\frac {m_{1}m_{2}}{d^{2}}$ where $F=the\quad force\quad of\quad gravity$ $G=universal\quad gravitational\quad constant$ $m_{1}$ and $m_{2}=masses\quad of\quad the\quad two\quad objects$ $d=the\quad distance\quad between\quad the\quad centers\quad of\quad the\quad two\quad objects$ What would result in the greatest gravitational force between two objects? A halving the mass of object 1 B doubling the mass of object 1 C halving the distance between the two objects D doubling the distance between the two objects

Which method has detected more planets around other stars? The astrometric method. Direct detection. The Doppler method. The transit method.

Find the conductivity of a conduit with a cross-sectional area of $0.750cm^{2}$ and a length of 15.0 cm, given that its conductance G is $0.500ohm^{-1}.$ $18ohm^{-1}cm^{-1}$ $10.0ohm^{-1}$ $2.0ohm^{-1}cm^{-1}$ $5.0ohm^{-1}cm^{-1}$

Define acoustic propagation property effects of the sound wave upon the medium effects of the medium upon the sound wave effects of the medium upon propagation speed effects of propagation speed upon the medium

When light is reflected from a smooth, plane mirror Multiple Choice the angle of reflection is the same as the angle of incidence. most of the light is scattered into multiple directions. the light is changed to a lower frequency. the wave characteristics are predominant.

When a light wave approaches a glass-air interface from the glass side at the critical angle, the angle of refraction is . __ $43^{\circ }$ $48^{\circ }$ o $45^{\circ }$

An example of the conversion of gravitationa potential energy into kinetic energy is a hockey puck sliding on ice. striking a match. a falling raindrop. a gasoline powered engine.