Question

A vehicle travels half the distance l with speed v₁ and the
other half with speed v₂, then its average speed is
(a) v₁ + v₂/2
(b) 2v₁ + v₂/v₁ + v₂
(c) 2v₁v₂/v₁ + v₂ (d) L(v₁ + v₂)/v₁v₂

Answer 1

Answer:

OPTION C

Explanation:

Formula for average speed=total distance/total time

Let distance traveled =L

time taken in completing first half distance

=L/2(v1).

time taken to complete second half distance

=L/2(v2).

so total time taken =L/2v2 + L/2v1

=L(v1+v2)/2v1v2.

so average speed=L/[L(v1+v2)/2v1v2]

=2v1v2/(v1+v2).

Answer 2

Answer:

The correct answer is kf = 1/kd

Explanation:

The dissociation constant or also known as kd is reverse of the freezing point depression constant also known as kf.

The 'k' denotes the word constant. Although there are many different meanings of the word 'k' in chemistry like for denoting temperature in kelvin, for potassium, for denoting equilibrium constant and here 'k' is used in the sense of a constant value.The correct answer is kf = 1/kd

Explanation:

The dissociation constant or also known as kd is reverse of the freezing point depression constant also known as kf.

The 'k' denotes the word constant. Although there are many different meanings of the word 'k' in chemistry like for denoting temperature in kelvin, for potassium, for denoting equilibrium constant and here 'k' is used in the sense of a constant value.