JAMB Physics Past Questions & Answers - Page 188

936.

An air force jet flying with a speed of 335ms-1 went past an anti-aircraft gun. How far is the aircraft 5s later when the gun was fired?

A.

838m

B.

3350m

C.

670m

D.

1675m

E.

67m

Correct answer is D

Distance covered = speed x time

= 335 x 5

= 1675m

937.

The frictional force between two bodies?

A.

exists only when there is relative motion or tendency for motion

B.

acts so as to oppose the motion

C.

depends on the normal reaction between the two surfaces

D.

is relatively independent of the area in contact

E.

has all of these characteristics

Correct answer is E

Frictional force is the opposing force that is created between two surfaces that try to move in the same direction or that try to move in opposite directions.

The main purpose of a frictional force is to create resistance to the motion of one surface over the other surface.

938.

A man walks 1km due east and then 1km due north. His displacement is

A.

1 km N15oE

B.

1 km N30oE

C.

\(\sqrt 2\)km N 45oE

D.

\(\sqrt 2\)km N 60oE

E.

2km N 75oE

Correct answer is C

R = \(\sqrt{1^2 + 1^2}\) = \(\sqrt{2km}\)

\(\theta\) = tan-1 \(\frac{(1)}{1}\) = 45oC

= \(\sqrt 2\)km N 45oE

939.

Which of the following statements is correct? Silvered walls of a vacuum flask are used to prevent

A.

heat loss due to conduction

B.

vacuum loss

C.

heat entry into the inner flask due to convection

D.

heat loss due to radiation

E.

heat loss due to convection

Correct answer is D

No explanation has been provided for this answer.

940.

Radio carrier waves are generated by causing electrons to oscillate rapidly in

A.

a microphone

B.

a television camera

C.

an antenna

D.

coaxial cables

E.

a transmitter

Correct answer is E

No explanation has been provided for this answer.