JAMB Physics Past Questions & Answers - Page 429

2,141.
2,142.

A satellite is in a parking orbit if its period is

A.

less than the period of the earth

B.

more than the period of the earth

C.

equal to the period of the earth

D.

the square of the period of the earth

Correct answer is C

A satellite is said to be in a parking orbit if its period is exactly equal to the period of the earth as it turns its own orbit;. which is about 24hrs

2,143.

The stylus of a phonograph record exerts a force of 7.7 x 10-2N on a groove of radius 10-5m. Compute the pressure exerted by the stylus on the groove

A.

2.45 x 108 Nm-2

B.

3.45 x 108 Nm-2

C.

4.90 x 108 Nm-2

D.

2.42 x 108 Nm-2

Correct answer is A

No explanation has been provided for this answer.

2,144.

Water does not drop through an open umbrella of silk materials unless the inside of the umbrella is touched. This is due to

A.

capilarity

B.

osmotic pressure

C.

viscosity

D.

surface tension

Correct answer is D

Surface tension - The tendency of a liquid surface to behave as an elastic skin

2,145.

If an object just begins to slide on a surface inclined at 30o to the horizontal,the coefficient of friction is

A.

√3

B.

√3/2

C.

1/√2

D.

1/√3

Correct answer is D

A body sliding down a plane inclined at 30o to the horizontal, has coefficient of friction
= tan 30o = 1/√3