Answer:
Measurement is a comparison of an unknown quantity with a known fixed quantity of the same kind. The value obtained on measuring a quantity is called its magnitude. The magnitude of a quantity is expressed as numbers in its unit.
Explanation:
a)
Sum of moments = 0 (Equilibrium)
T . cos (Q)*L = m*g*L/2
b) If the String is shorter the Q increases; hence, Cos Q decreases which in turn increases Tension in the string due to inverse relationship!
c)
Answer: B. Increases
Explanation:
An electron is a negatively charged particle, while a proton is positively charged.
Opposites attract so as it approaches the proton the force of attraction will increase.
Answer:
(a) W = 8.66 J
(b) Velocity = 2.40 m/s
Explanation:
(a) Work done is given as the product of force and displacement. That is:
W = F * d * cos(A)
Where F = force applied
d = distance moved
A = angle of ramp
Therefore, work done is:
W = 20 * 0.5 * cos30
W = 8.66 J
(b) Work done is equal to change in Kinetic energy. Since the initial kinetic energy is zero:
W = KE(final)
W = ½ * m * v²
Where v = final velocity
=> 8.66 = ½ * 3 * v²
v² = 5.773
v² = 2.40 m/s
Answer:
0.21%
Explanation:
We are given;
Mass; m = 100 kg
Diameter; d = 2.2 mm = 2.2 × 10^(-3) m
Young's modulus; E = 12.5 x 10^(10) N/m².
Formula for area is;
A = πd²/4
A = (π/4) x (2.2 x 10^(-3))²
A = 3.8 x 10^(-6) m²
Force; F = mg
g is acceleration due to gravity and has a constant value of 9.8 m/s²
F = 100 × 9.8
F = 980 N
Formula for young's modulus is;
E = Stress/strain
Formula for stress = F/A
Formula for strain = ΔL/L
Thus;
E = (F/A)/(ΔL/L)
Making ΔL/L the subject, we have;
ΔL/L = (F/A)/E
Plugging in the relevant values;
ΔL/L = 980/(3.8 x 10^(-6) × 12.5 × 10^(10))
ΔL/L = 0.0021
Then percentage increase in length of a wire = 0.0021 × 100% = 0.21%
