1991 - WAEC Physics Past Questions and Answers - page 1
1
Which of the following is a fundamental quantity?
A
speed
B
density
C
lenght
D
impulse
correct option: c
Users' Answers & Comments2
A body moves with a constant speed but has an acceleration. this process if it
A
moves in a straight line
B
moves in a circle
C
is oscillating
D
is in equilibrum
correct option: b
Users' Answers & Comments3
A ball is projected horizontally from the top of a hill with a velocity of 20m-1. If it reaches the ground 4 seconds later, what is the height of the hill? (g = 10ms-2)
A
20m
B
40m
C
80m
D
160m
correct option: c
Initial horizontal velocity = 20ms-1
Initial vertical velocity = 0
s = ut + \(\frac{1}{2}gt^2\) = 0 x 5 x 42
= 80m
Users' Answers & CommentsInitial vertical velocity = 0
s = ut + \(\frac{1}{2}gt^2\) = 0 x 5 x 42
= 80m
4
A body moving with uniform acceleration has two points(5, 15) and (20, 60) on the velocity-times graph of its motion. Calculate
A
0.25ms-2
B
3.00ms-2
C
4.00ms-2
D
9.00ms-2
correct option: b
slope = acceleration
a = \(\frac{v_2 - v_1}{t_2 - t_1} = \frac{60- 15}{20 - 5}\)
= 3ms-2
Users' Answers & Commentsa = \(\frac{v_2 - v_1}{t_2 - t_1} = \frac{60- 15}{20 - 5}\)
= 3ms-2
5
the diagram above shows the position of a simple pendulum set in motion. At which of the positions does the pendulum have maximum kinetic energy?
A
5
B
4
C
3
D
2
correct option: c
Users' Answers & Comments6
An orange fruit drops to the ground from the top of a tree 45m tall. How long does it takes to reach the ground? (g = 10ms-2)
A
3.0s
B
4.5s
C
6.0s
D
7.5s
7
power is defined as the
A
capacity to exert a force
B
product of force and time
C
product of force and distance
D
ability to do work
correct option: e
Users' Answers & Comments8
The product PV where P is pressure and V is volume has the same unit as
A
power
B
work
C
acceleration
D
impulse
9
The diagram represents a block-and-tackle pulley system on which an effort of 50N is just able to lift a load of weight W. If the efficiency of the machine is 40%. find the value of W
A
300N
B
200N
C
140N
D
120N
correct option: d
Eff = \(\frac{MA}{VR}\) x 100%
40 = \(\frac{MA}{60}\)
MA = 240
\(\frac{L}{E} = \frac{240}{100}\)
W = L = \(\frac{240}{100}\) x 50
= 120N
Users' Answers & Comments40 = \(\frac{MA}{60}\)
MA = 240
\(\frac{L}{E} = \frac{240}{100}\)
W = L = \(\frac{240}{100}\) x 50
= 120N
10
A boatman facing north wants to cross a flowing river to a point directly opposite its position at the other bank. If the river is flowing eastwards, in what direction should he row his boat?
A
west
B
east
C
north-west
D
north-east
correct option: c
Users' Answers & Comments