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.

616.

A football is kicked at an angle of 45° to the horizontal over a defense line up with a velocity of 15\(ms^{-1}\). Calculate the magnitudeof horizontal velocity of the ball at its highest point  [Neglect friction, g = 10\(ms^{-2}\)].

A.

0.0\(ms^{-1}\)

B.

5.6\(ms^{-1}\)

C.

10.6\(ms^{-1}\)

D.

15.0\(ms^{-1}\)

Correct answer is C

The horizontal component of velocity, \(V_{x}\), is unaffected by the acceleration of free fall and remains constant.

\(V_{x} = U_{x} = Ucos\theta\)

= \(15 \times cos45 = 15\times 0.7071\)

\(\approxeq 10.6ms^{-1}\)

617.

The graph of density against temperature for water is correctly illustrated by

A.

I

B.

II

C.

III

D.

IV

Correct answer is C

No explanation has been provided for this answer.

618.

According to Newton's law of cooling, the heat energy lost per unit area of a body depends on the

I. Surface area

II. Nature of the surface

III. Temperature of the surface

IV. Excess temperature over the surroundings

A.

I and II only

B.

II and IV only

C.

I,II and III

D.

I, II and IV

Correct answer is C

The rate of cooling of liduid according to Newton's law of cooling depends on:

- Temperature of the liquid

- Temperature of the enclosure

- The area of the exposed surface

- The nature and extent of the surface of the containing vessel

619.

An object at rest is said to possess 

A.

potential energy

B.

kinetic energy

C.

chemical energy

D.

electrical energy

Correct answer is A

Potential energy is the energy that is stored in an object due to its position relative to some zero position

620.

A body is projected with an initial velocity u at angle \(\theta\) to the horizontal. If \(R_{max}\) is the maximum range of the projectile, what does the relation \(\frac{u^{2}}{R_{max}}\) represent?

A.

The vertical distance covered

B.

Acceleration due to gravity

C.

The horizontal distance covered

D.

The acceleration of the body

Correct answer is B

\(R_{max} = \frac{u^{2}}{g}\)

Hence, \(g = \frac{u^{2}}{R_{max}}\)