Explain why a balloon filled with air cannot float in the middle of a room without moving downwards but a helium balloon of the same size can?

What is different between an ionic bond and a covalent bond?

How do the properties of salt compare with the properties of sodium and chlorine

What are we calculating when we calculate expected frequencies? What is the reason for calculating expected frequencies the way we do? In laymen's terms, what do expected frequencies tell us?

What type of reaction is shown below? 2Mg+O2->2MgO

How much time is needed for a car to accelerate from 8.0 m/s to speed of 22 m/s if the acceleration is 3.0 m/s^2?

An example of a stable system

What causes chemical weathering? a. damage caused by animals and plants c. natural acids b. ice wedging d. physical factors

1. Strzała o masie 20 g tuż po wystrzale ma prędkość 50 m/s. Oblicz pracę wykonaną przez zawodniczkę. Ile wynosi energia potencjalna sprężystości napiętej cięciwy? 2. Na trampolinę o współczynniku sprężystości k=2 kN/m stanął zawodnik o masie 80 kg.

Two small plastic spheres between them has magnitude 0.22 N. What is the charge on each sphere is one the other? Explain whether it can be determined from the information give, whether the charges are positive or negative.

If it has enough kinetic energy, a moleculeat the surface of the Earth can escape the Earth's gravitation. The acceleration of gravity is 9.8 m/s2, and the Boltzmanns' constant is 1.38066*10-23 J/K.