A roller coasters velocity at the top of a hill is 21mls. Two seconds later it reaches the bottom of the hill with a velocity of 36mls. What is the acceleration of the roller coasters

7.5 m/s²

Explanation:

The following data were obtained from the question:

Initial velocity (u) = 21 m/s

Final velocity (v) = 36 m/s

Time (t) = 2 secs

Acceleration (a) =..?

The acceleration of an object is simply defined as the rate of change of velocity of the object with time. Mathematically, it is represented as:

Acceleration (a) = (final velocity (v) – initial velocity (u)) / time (t)

a = (v – u)/t

With the above formula, we can determine the acceleration of the roller coaster as follow:

a = (v – u)/t

a = (36 – 21)/2

a = 15/2

a = 7.5 m/s²

Therefore, the acceleration of the roller coaster is 7.5 m/s².

hydrocarbons are organic compounds that contain only hydrogens and carbons. they can be saturated (those which contain only carbon-carbon single bonds) or unsaturated (those which contain carbon-carbon double or triple bonds) in nature. hydrocarbons can undergo several reactions like substitution, elimination etc.  

on substituting one or more hydrogen atoms in hydrocarbon it results in the formation of haloalkane. as the halogen atoms are large compared to the carbon and hydrogen atoms, due to which the molecular weight increases and the bond become polar because of presence electronegative halogen atom and results in the increase in boiling point of the haloalkane.

thus, the correct option is (b) that is the boiling point of the new compound increases on substituting a hydrogen atom with a halogen in a hydrocarbon.