*2017 PRIVATE WASSCE PHYSICS ESSAY*
*1-10- ACBAABCABC*
*11-20- CADDCBABBA*
*21-30- CABADBCCCA*
*31-40- BAABCACACB*
*41-50- ABBACBADAB*
*READ BEFORE YOU SHADE*
*VERIFIED AND confirmed*
*Question one*
(a) Horizontal speed just before it strikes floor = ucos(theta)
= 10cos0°
= 10 m/s
(b) t = √(2g/h)
= √(2*10*1)
= √20
= 4.47s
Question 4
(a) given: u = 20m/s
t = 4s
g = 10m/s²
h = ?
Using s = ut - ½gt²
s = 20(4) - ½(10)(4)²
s = 0m
(b) The inference is that after 4s, the ball returns back to the plane of projection
Question 3
Magnetic materials: ¶ Iron ¶ Cobalt ¶ Nickel
Question 2
¶ medical uses
¶ welding and cutting
¶ military uses for defense and counter measures
Question 5
The factors that determine the location of a solar power station are
¶ Intensity of sun light
¶ surface slope
¶ feeder capacity of the distribution center
Physics
8ai)
Force is a push or pull which changes a body's state of rest or uniform motion in a straight line.
II)a) field force
b) contact force
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8bi)
Bodies streamlined in
Shape move through fluid so as to oppose or overcome the motion of the fluid
II) a) fish
B) submarine
==================
8c)
Mass= 1.3 kg
F= 1.2 m
V= 7.0 m/s
Drawing
II) Acceleration
Note , V²= U² + 2as
Where S=r=1.2 m
(7.0)²= 0²+2× a (1.2)
= 49/2.4 = 2.4a/2.4
a = 20.4
B) Force=?
From force = MA
Force =1.3×20.4
Force =25.52
=========={={{{{{{============
*Question 9*
(a) Poor conductors of heat application: ¶ Coat (Trapped air in between the fabric)
¶ The hair and the fur of animals are bad conductors of
heat and they protect them from cold .
(b) Renewable: Water, corn stalk
Non-renewable: coal, natural gasgas
(c) A closed is a physical system so far removed from other systems that it does not interact with them.
d) heat required to melt = mc∆ + ml
*NB*: Not sure of the temperature given, if it is -3°C or -5°C, However, *Using -3°C*
Heat = (0.1×2200×3)+(0.1×2.26×10^6)
= 226660 J
e) (i) Given: 75 heart beats in 1 min
Therefore in 1 hour, we have (75×60) heart beats = 4500 heart beats
Also given: 2J of energy is expended in 1 heart beat
Therefore for 4500 heart beats, energy expended = (4500×2) J = 9000J
e) (ii) Energy = mc∆
9000 = (0.25×4200×∆)
9000 = 1050∆
∆ = 9000/1050
Temperature rise = 8.57°C
========={={{===================
*Question 11*
(a) ¶ Electrical method
¶ Contact method
(b) Electric lines of force are imaginary lines drawn in an electric field in such a way that the direction at any point gives the direction of the electric field at such a point
(c) QR = SP
(d) Resistivity is the resistance of a unit length of material of unit cross-sectional area
d) heat required to melt = mc∆ + ml
*NB*: Not sure of the temperature given, if it is -3°C or -5°C, However, *Using -3°C*
Heat = (0.1×2200×3)+(0.1×2.26×10^6)
= 226660 J
(e) Given: F = 50Hz
L = 10 mH (10×10^-³H)
Inductive reactance, XL = 2πFL
= 2×3.14×50×10×10^-³
= 3..14 ohms
(f) If voltmeter reads 12V, over the 500 ohms, then using I = V/R
current in the circuit is I = 12/500
I = 0.024A
Hence over the 200 ohms, V = IR
V = 0.024×200
V = 4.8 VOLTS
Voltmeter will read 4.8 volts
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