Correct question is;
A thermal tap used in a certain apparatus consists of a silica rod which fits tightly inside an aluminium tube whose internal diameter is 8mm at 0°C.When the temperature is raised ,the fits is no longer exact. Calculate what change in temperature is necessary to produce a channel whose cross-sectional is equal to that of the tube of 1mm. (linear expansivity of silica = 8 × 10^(-6) /K and linear expansivity of aluminium = 26 × 10^(-6) /K).
Answer:
ΔT = 268.67K
Explanation:
We are given;
d1 = 8mm
d2 = 1mm
At standard temperature and pressure conditions, the temperature is 273K.
Thus; Initial temperature; T1 = 273K,
Using the combined gas law, we have;
P1×V1/T1 = P2×V2/T2
The pressure is constant and so P1 = P2. They will cancel out in the combined gas law to give:
V1/T1 = V2/T2
Now, volume of the tube is given by the formula;V = Area × height = Ah
Thus;
V1 = (πd1²/4)h
V2 = (π(d2)²/4)h
Thus;
(πd1²/4)h/T1 = (π(d2)²/4)h/T2
π, h and 4 will cancel out to give;
d1²/T1 = (d2)²/T2
T2 = ((d2)² × T1)/d1²
T2 = (1² × T1)/8²
T2 = 273/64
T2 = 4.23K
Therefore, Change in temperature is; ΔT = T2 - T1
ΔT = 273 - 4.23
ΔT = 268.67K
Thus, the temperature decreased to 268.67K
Answer:
b. negative
Explanation:
neutrons have a negative charge and protons have a proton has a positive charge
Mass (m)=55kg
acceleration (a)=9.81 m/s^2, this is the acceleration due to gravity.
initial velocity=0m/s. The skydiver doesn’t start with any speed because she is on the plane or helicopter.
final velocity=16m/s This is the velocity (speed) the skydiver reaches
The equation we use is KE=.5mv^2
Kinetic energy=.5 mass x velocity^2
KE=.5(55kg)(16m/s)^2
KE=.5(55kg)(256m/s)
KE=.5(14080J)
J=Joules
KE=7040J
Kinetic energy is 7040 Joules (J)
Hope this helps
C, they didn't know any better
Answer:
8.37×10⁻⁴ N/C
Explanation:
Electric Field: This is the ratio of electrostatic force to electric charge. The S.I unit of electric field is N/C.
From the question, the expression for electric field is given as,
E = F/Q.......................... Equation 1
Where E = Electric Field, F = force experienced by the charged balloon, Q = Charge on the balloon.
Given: F = 8.2×10⁻² Newton, Q = 9.8×10 Coulombs = 98 Coulombs
Substitute these values into equation 1
E = 8.2×10⁻² /98
E = 8.37×10⁻⁴ N/C
Hence the Electric Field of the charged balloon = 8.37×10⁻⁴ N/C