NECO Physics Past Questions & Answers - Page 38

186.

A stone is released from a height of 80m above the ground. Calculate its velocity just before it strikes the ground. (g=10ms-2)

A.

25ms-1

B.

40 ms-1

C.

55 ms-1

D.

65ms-1

E.

80 ms-1

Correct answer is B

No explanation has been provided for this answer.

187.

A constant force of 5N acts for 5s on a mass of 5kg initially at rest. Calculate the final momentum of the mass.

A.

125 kgms-1

B.

75 kgms-1

C.

25 kgms-1

D.

20 kgms-1

E.

5 kgms-1

Correct answer is C

According to Newton's second law of motion, \(force =  \frac{ final momentum - initial momentum}{time}\)

but momentum = mass x velocity; F= 5N, Initial mass = 5kg, time = 5secs, initial velocity = zero

then final momentum = force x time (since initial momentum of the mass = 0, that is  5 x 0)

= 5 x 5 = 25 kgms-1

 

188.

The motion of the prongs of a sounding turning fork is

A.

circular

B.

oscillatory

C.

random

D.

rotational

E.

translational

Correct answer is B

No explanation has been provided for this answer.

189.

The resistance of a series R-C circuit is 5 ω If the impedance of the circuit is 13 ω calculate the reactance of the capacitor

A.

12 Ω

B.

14 Ω

C.

16 Ω

D.

18 Ω

E.

65 Ω

Correct answer is A

No explanation has been provided for this answer.