A box full of charged plastic balls sits on a table. The electric force exerted on a ball near one upper corner of the box has components 1.2 x 10^-3 N directed north, 5.7 x 10^-4 N directed east and 2.2 x 10^-4 N directed vertically upward. The charge on this ball is 110 nC. If this ball were replaced with one that has a charge of -50nC , what would be the force components exerted one the replacement ball?

F north=?
F east=?
F up=?​

Asample of a gaseous substance changes into liquid. this process is called (blank) and it takes place when heat is (blank) a gaseous system

True or false when elements combine to form a mixture, the resulting chemical properties may be very different from those of the elements that make it.

The frequency of vibrations of a vibrating violin string is given by f = 1 2l t ρ where l is the length of the string, t is its tension, and ρ is its linear density.† (a) find the rate of change of the frequency with respect to the following. (i) the length (when t and ρ are constant) (ii) the tension (when l and ρ are constant) (iii) the linear density (when l and t are constant) (b) the pitch of a note (how high or low the note sounds) is determined by the frequency f. (the higher the frequency, the higher the pitch.) use the signs of the derivatives in part (a) to determine what happens to the pitch of a note for the following. (i) when the effective length of a string is decreased by placing a finger on the string so a shorter portion of the string vibrates df dl 0 and l is ⇒ f is ⇒ (ii) when the tension is increased by turning a tuning peg df dt 0 and t is ⇒ f is ⇒ (iii) when the linear density is increased by switching to another string df dρ 0 and ρ is ⇒ f is ⇒