Physics questions and answers

Physics Questions and Answers

If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.

2,306.

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.

2,307.

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

2,308.

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.

2,309.

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.

2,310.

A weight of 1000 grams hangs from a lever 20cm to the fulcrum. At the left is a 500-gram weight 20cm from the fulcrum, and a 200-gram weight x cm away from the fulcrum. What is the value of x that will make the lever balanced?

A.

50cm

B.

20cm

C.

10cm

D.

30cm

E.

70cm

Correct answer is D

Taking moment about F,

200(X + 20) + (500 x 20) = (1000 x 20)

200X + 4000 + 10000 = 20000

200X + 14000 = 20000

200X = 20000 - 14000

200X = 6000

X = 30cm