Physics 2020 Waec Past Questions and Answers

Question 21 :

• WAEC 2020

The velocity of sound in air at 15°C is 35400ms\(^{-1}\). Calculate the velocity at 47\(^o\)C

A. 790ms\(^{-1}\)
B. 602ms\(^{-1}\)
C. 358ms\(^{-1}\)
D. 322ms\(^{-1}\)

Question 22 :

• WAEC 2020

Which of the current-voltage characteristics shown below is that exhibited an ohmic conductor?

A. A
B. B
C. C
D. D

Question 23 :

• WAEC 2020

A 500N box rests on a horizontal floor. A constant horizontal force is exerted on the box so that it moves through 8m. If the coefficient of kinetic friction between the floor and the box is 0.22, calculate the workdone on the box

A. 880J
B. 440J
C. 400J
D. 110J

Question 24 :

• WAEC 2020

The diagram illustrates a ball of mass m sliding down a plank inclined at an angle of 0 to the horizontal. The kinetic friction between the ball and the plank is F and acceleration of free fall is g. The normal force on the ball is?

A. Mgsin \(\theta\)
B. Mgtan \(\theta\), mgcos \(\theta\)
C. Mgcos \(\theta\)
D. Mgcot \(\theta\)

Question 25 :

• WAEC 2020

The diagram above illustrates a ball of mass m sliding down a plank inclined at an angle of 0 to the horizontal. The kinetic friction between the ball and the plank is F and the acceleration of free fall is g. The net force on the ball along the plank is?

A. Mgsin \(\theta\) + F
B. F - mgcos \(\theta\)
C. Mgsin \(\theta\) - F
D. F + mgcos \(\theta\)