Answer:
The percentage change in resistance of the wire is 69%.
Explanation:
Resistance of a wire can be determined by,
R = (ρl) ÷ A
Where R is its resistance, l is the length of the wire, A its cross sectional area and ρ its resistivity.
When the wire is stretched, its length and area changes but its volume and resistivity remains constant.
= 1.3l, and 
= 
So that;
= (ρ) ÷ = (ρ × 1.3l) ÷ ()
= (1.3lρ) ÷ ()
= 
× [(ρl) ÷ A]
= 1.69R (∵ R = (ρl) ÷ A)
= 1.69R
Where is the new resistance, is the new length, and is the new area after stretching the wire.
The change in resistance of the wire = - R
= 1.69R - 1R
= 0.69R
The percentage change in resistance = 
× 100
= 0.69 × 100
= 69%
The percentage change in resistance of the wire is 69%.
Answer:
m = 48.93kg
The load is 48.93kg.
Explanation:
Given;
Power P = 100watts
Efficiency e = 60% = 0.60
distance d = 10 m
time taken t = 80 s
Acceleration due to gravity g = 9.81m/s
Workdone W can be expressed as;
W = ePt = Fd = mgd
ePt = mgd
Making m the subject of formula;
m = ePt/gd
Substituting the values;
m = (0.60×100×80)/(9.81×10)
m = 48.93kg
The load is 48.93kg.
1,000 grams = 1 kilogram
20 grams = 0.02 kilogram
Kinetic energy = (1/2) (mass) x (speed)²
(1/2) (0.02) x (15)² =
(0.01) x (225) = 2.25 joules
Answer: B. Rhyolitic
Rhyolitic magma is responsible for most violent volcanic eruptions. Rhyolitic magma erupts catastrophically with high intensity gas content. This magma being more viscous traps gases, builds pressures and erupts explosively. High viscosity of this magma is because of high silica content that erupt with the mineral contents of the rocks.
