WAEC Further Mathematics Past Questions & Answers - Page 36

176.

Solve, correct to three significant figures, (0.3)\(^x\) =  (0,5)\(^8\)

A.

4.61

B.

4.606

C.

0.461

D.

0.0130

Correct answer is A

(0,3)\(^x\) = (0.5)\(^8\) 

xlog 0,3 = 9 log 0.5

x = \(\frac{8 \log 0.5}{\log 0.3}\)

= 4.606

177.

A 35 N force acts on a body of mass 5 kg for 2 seconds. Calculate the change in momentum of the body.

A.

70 kg ms\(^{-1}\)

B.

55 kg ms\(^{-1}\)

C.

50 kg ms\(^{-1}\)

D.

35 kg ms\(^{-1}\)

Correct answer is A

Change in momentum 

= F x t = 35N x 2 

= 70kg ms\(^{-1}\) 

178.

Which of these inequalities is represented by the shaded portion of the graph? 

A.

2y + x - 3 < 0

B.

2y - x - 3 < 0

C.

2y - x + 3 < 0

D.

2y + x +3 < 0

Correct answer is B

(0, 1.5), (-3, 0) 

m = \(\frac{0 - 1.5}{-3, 0}\) = 0.5

0.5 = \(\frac{y - 1.5}{-3.0}\) = 0.5

y = 0.5x + 1.5 

2y = x + 3

2y - x - 3 < 0

179.

Find the constant term in the binomial expansion of (2x\(^2\) +  \(\frac{1}{x^2}\))\(^4\)

A.

10

B.

12

C.

24

D.

42

Correct answer is B

6(2x\(^2\))\(^2\) (\(\frac{1}{x^2}\))\(^2\)  

= 6 x 2

= 12

180.

A particle starts from rest and moves in a straight line such that its velocity, V ms\(^{-1}\), at time t second is given by V = 3t\(^2\) - 6t. Calculate the acceleration in the 3rd second. 

A.

0 ms\(^{-2}\)

B.

3 ms\(^{-2}\)

C.

6 ms\(^{-2}\)

D.

9 ms\(^{-2}\)

Correct answer is C

V = 3t\(^2\) - 6t

\(\frac{dx}{dt}\) = 6r - 6

at t = 4

\(\frac{dx}{dt}\) = 6 x 4 - 6 = 24 - 6

= 18

at t = 3

\(\frac{dy}{dt}\) = 6 x 4 - 6 

= 24 - 6

= 18 

at t = 3

\(\frac{dx}{dt}\) = 6 x 3 - 6 = 18 - 6

= 12

\(\frac{dy}{dt}\) = 18 - 12 

= 6ms\(^{-2}\)