JAMB Physics Past Questions & Answers - Page 271

1,351.

40m3 of liquid is mixed with 60m3 of another liquid Q. If the density of P and Q are 1.00kgm-3 and 1.6kgm-3 respectively, what is the density of the mixture?

A.

0.05kgm-3

B.

1.25kgm-3

C.

1.30kgm-3

D.

1.36kgm-3

Correct answer is D

Mp = 1 x 40 = 40kg ; mQ = 1.6 x 60 = 96kg

volume of mixture = 40 + 60 = 100m3

mass of mixture = 40 + 96 = 136kg

density of mixture = \(\frac{136}{100}\)

= 1.36kgm3

1,352.

An inclined plane which makes an angle of 30o  with the horizontal has a velocity ratio of

A.

2

B.

1

C.

0.866

D.

0.50

Correct answer is A

V.R = \(\frac{1}{sin\theta}\)

= \(\frac{1}{sin30}\)

= 2

1,354.
1,355.

To keep a vehicle moving at a constant speed v, requires power P, from the engine. The force provided by the engine is

A.

\(\frac{p}{v}\)

B.

\(\frac{1}{2}\) v

C.

pv

D.

\(\frac{p}{v^2}\) v

Correct answer is A

power = speed x force

force = \(\frac{power}{speed}\)