How big is observable universe? How do we know that?

Democritus thought that matter was made of tiny particles. true or false

Two charged particles, one of charge + q and one of charge - 2q are separated by a distance d. Which particle will experience a greater electrostatic force from the other particle?

A small glass bead has been charged to + 30 nC. A tiny ball bearing 1.0 cm above the bead feels a 1.8*10^-2 N downward electric force. What is the charge on the ball bearing?

Ep-40 if you run aground in an outboard boat and you are not taking on water, what is the first step in attempting to free your vessel?

What is a constant variable?

A 160 kilogram cannon fires a 30 kilogram cannonball with a speed of 45 m/s at an angle of 30 degrees with the horizontal. In what direction and at what speed does the cannon recoil?

A student uses an indicator to measure the pH of a solution. The indicator shows a pH of 7. What must be true of this solution? The solution contains neither hydronium ions nor hydroxide ions.

What is the purpose of a valve?

A particle travels 15 times around a 10-cm radius circle in 42 seconds. what is the average speed (in m/s) of the particle?

Where are the magnetic fields stronger near a bar magnet? A) Top B) Center C) Ends D) Bottom