JAMB Physics Past Questions & Answers - Page 110

546.

A projectile is fired from the ground level with a velocity of 300ms-1 at an angle of a 30o to the horizontal.
Calculate the time taken to reach the maximum height?
[g = 10ms-2]

A.

30s

B.

20s

C.

25s

D.

15s

Correct answer is D

The total time of flight is given as

\(T = \frac{2usin\theta}{g}\)

Hence, time to maximum height is half of the total time of flight, 

t = \(\frac{u sin\theta}{g}\)

= \(\frac{300 \text {sin} 30}{10}\) = 15s

548.

What force has to be exerted on a mass 60kg to give it an acceleration of 10ms-2 vertically upwards?
[g = 10ms-2]

A.

300N

B.

600N

C.

1200N

D.

400N

Correct answer is C

F = Ma + mg = 60 x 10 x 60 x 10 = 1200N

549.

A saturated vapour pressure of a liquid increases when the

A.

Temperature of a liquid increases

B.

Volume of the liquid increases

C.

Volume of the liquid decreases

D.

Temperature of the liquid decreases

Correct answer is A

No explanation has been provided for this answer.

550.