Answer:
u_e = 9.3 * 10^-8 J / m^3 ( 2 sig. fig)
Explanation:
Given:
- Electric Field strength near earth's surface E = 145 V / m
- permittivity of free space (electric constant) e_o = 8.854 *10^-12 s^4 A^2 / m^3 kg
Find:
- How much energy is stored per cubic meter in this field?
Solution:
- The solution requires the energy density stored between earth's surface and the source of electric field strength. The formula for charge density is given by:
u_e = 0.5*e_o * E^2
- Plug in the values given:
u_e = 0.5*8.854 *10^-12 *145^2
u_e = 9.30777 * 10^-8 J/m^3
Explanation:
The correct answers to the fill in the blanks would be;
1. Viscoelastic stress relaxation refers to scenarios for which the stress applied to a polymer must decay over time in order to maintain a constant strain. Otherwise, over time, the polymer chains will slip and slide past one another in response to a constant applied load and the strain will increase (in magnitude).
2. Viscoelastic creep refers to scenarios for which a polymer will permanently flow over time in response a constant applied stress.
The polymer whose properties have been mentioned above is commonly known as Kevlar.
It is mostly used in high-strength fabrics and its properties are because of several hydrogen bonds between polymer molecules.
Answer:
The correct answer is option 'B': Load is far from fulcrum and the effort is applied near the fulcrum
Explanation:
A lever works on the principle of balancing of torques. The torque about the fulcrum by the load should be equal to the torque by the applied effort. Since we know that the torque is proportional to both the force and the distance it is applied from the distance from the axis of rotation. A lever is used when we need to lift a heavy load by utilizing this effect of the lever arm.
A mechanical disadvantage occurs when we are not able to lift the weight easily due to the fact we apply effort near the fulcrum.
