Why are galaxies visible

A Cannon makes a noise, and it's echo is heard 4.5 seconds later. if sound travels at 343 m/s: a.) how far did the sound travel? b.) how far away is the surface it reflected off of?

Which of the following best describes the impact of rainforest deforestation on global precipitation? a. The average global level of precipitation increases. b. The average global level of precipitation decreases. c.

1. an arrow is fired directly horizontal off a cliff that is 15.0 meters tall with a velocity of 60.5m/s. A. how long is the arrow in the air? B. what range (Δx) of the arrow?

Which of these statements explains the difference between nuclear binding energy and the strong nuclear force? Check all that apply.

At t=0, an object of mass m is at rest at x=0 on a horizontal, frictionless surface. A horizontal force Fx=F0 (1-t/T), which decreases from F0 at t=0 to zero at t=T, is exerted on the object.

Why do space suits need to be pressurized?

Why do comets have tails?

The main characteristic of all vertebrates is the presence of a. cartilage b. a large brain c. a backbone d. an exoskeleton I got it. The answer was B

A projectile is thrown upward so that its distance above the ground after t seconds is h (t) equals negative 16 t squared plus 704 t. a) Find the maximum height the object reaches. b) Find the time it takes the object to reach the ground.

You are standing 100 meters from an object emitting a sound of constant intensity (loudness). You walk toward the source of sound until you are 20 meters from it. From your perspective, what has happened to the intensity of the sound?