The word igneous comes from the Latin word for fire. However, the name is inaccurate. The rocks are not created with flames. Instead, they are created when magma cools and hardens. Magma is hot molten rock found deep in the earth. Igneous rock is either intrusive or extrusive. It is intrusive when it forms inside the earth's crust. It is extrusive when it is formed above the earth's surface. Select the statement that explains how igneous rock is formed.
Question 9 options:

Molten rock found inside the earth cools and hardens.

Existing rocks are heated in fire until they melt.

Ash from volcanos falls and compresses into layers of rock.

Pressure below the surface forces rocks to smash together.

What are the factors that affect the resistance of a wire?

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 ⇒

Abookcase has a mass of 38 kg and the coefficient of friction between it and the floor is 0.82 what is the maximum force of friction between the bookcase and the floor a 372n b 305n c 412n d 449n