Answer:
C. Equals the sum of all forms of energy contained within the system.
D. Equals the heat entering the system at constant volume.
E. Equals the heat entering the system plus the work done on the system
Explanation:
Internal energy is defined as the sum of internal kinetic energy and internal potential energy, that is, the energy contained within the system.
The first law of thermodynamics relates the change in the internal energy with the heat entering the system (Q) and work done on the system (W), with the following expression:
If the system is at constant volume the work done is zero. Therefore, the heat entering the system increases its internal energy:
An insulator is a material that provides resistance to the flow of electric current. Insulators include rubber, plastic, glass since they do not allow electricity to flow through them.
Answer:
Therefore the resistance of the conductor is 175Ω
Explanation:
Resistance:
- Resistance of a metallic conductor is directly proportional to its length(l).
- Resistance of a metallic conductor is inversely proportional to its cross section area(A).
The notation sign of resistance is R.
The unit of resistance is ohm (Ω).
Therefore,
and
ρ is the proportional constant.
It is also known as resistivity of that metal.
Given ρ=35×10⁻⁶Ω-m
l= 20 m
A= 4.0×10⁻⁶m²
=175Ω
Therefore the resistance of the conductor is 175Ω
Answer:
5.3 m/s
Explanation:
First, find the time it takes for him to fall 7m.
y = y₀ + v₀ t + ½ at²
0 = 7 + (0) t + ½ (-9.8) t²
0 = 7 − 4.9 t²
t ≈ 1.20 s
Now find the velocity he needs to travel 6.3m in that time.
x = x₀ + v₀ t + ½ at²
6.3 = 0 + v₀ (1.20) + ½ (0) (1.20)²
v₀ ≈ 5.27 m/s
Rounded to two significant figures, the man must run with a speed of 5.3 m/s.
