Question 4721:

The linear expansivity of a substance is \(1,2 \times 10\) \(4 / K\). A cube of this substance has a volume of \(8.0 \times 103 cm 3\) at \(300< C >\)
Calculate the increase in itsvolumeat \(800 C\)

A. \(48 cm 3\)
B. \(24 cm 3\)
C. \(96 cm 3\)
D. \(72 cm 3\)

Question 4722:

Which of the following statement about liquid pressure is NOT correct?

A. At a point in a liquid is proportional to the depth
B. At any point in a liquid is the same at the same level
C. Is exerted equally in all directions at any point
D. Of a liquid at any point of its container acts in a direction perpendicular to the wall
E. At a particular depth depends on the shape of the vessel

Question 4723:

A ship traveling towards a cliff receives the echo of its whistle after \(3.5\) seconds. A short while later, it receives the echo after \(2.5\) seconds. If the speed of sound in air under prevailing conditions is \(250 \mathrm{~m} / \mathrm{s}\), how much closer is the ship to the cliff?

A. \(10 \mathrm{~m}\)
B. \(125 \mathrm{~m}\)
C. \(175 \mathrm{~m}\)
D. \(350 \mathrm{~m}\)
E. \(1000 \mathrm{~m}\)

Question 4724:

A force of \(16 \mathrm{~N}\) is applied to a \(4.0 \mathrm{~kg}\) block that is at rest on a smooth horizontal surface. What is the velocity of the block at \(t=\) 5 seconds?

A. \(4 \mathrm{~m} / \mathrm{s}\)
B. \(10 \mathrm{~m} / \mathrm{s}\)
C. \(20 \mathrm{~m} / \mathrm{s}\)
D. \(50 \mathrm{~m} / \mathrm{s}\)
E. \(80 \mathrm{~m} / \mathrm{s}\)

Question 4725:

The distance travelled by a particle starting from rest is plotted against the square of the time elapsed from the commencement of motion. The resulting graph is linear. The slope of this graph is a measure of

A. Initial displacement
B. Initial acceleration
C. Acceleration
D. Half the acceleration
E. Half the initial velocity