When you rub a balloon on a sweater, for example, some electrons come off and end up on the balloon. The fibers have lost electrons giving them a positive charge. The rubber gained electrons giving it a negative charge. ... The positively charged fibers are now attracted to the negatively charged balloon.
Answer:
19.68 × 10⁻³ m
Explanation:
Given;
Original Length, L₁ = 41.0 m
Temperature Change, ΔT = 40.0°C
Thermal Linear expansion of steel is given to be, ∝
= 12 × 10⁻⁶ /°C
Generally, Linear expansivity is expressed as;
∝ = ΔL / L₁ΔT
Where
∝ is the Linear expansivity
ΔL is the change in length, L₂ - L₁
L₂ is the final length
L₁ is the original length
ΔT is the change in temperature θ₂ - θ₁ (Final Temperature - Initial Temperature)
From equation of linear expansivity
ΔL = ∝
L₁ΔT
ΔL = 12 × 10⁻⁶ /°C × 41.0 m × 40.0 °C
ΔL = 19.68 × 10⁻³ m
ΔL = 19.68 mm
Answer:
The amount of work done required to stretch spring by additional 4 cm is 64 J.
Explanation:
The energy used for stretching spring is given by the relation :
.......(1)
Here k is spring constant and x is the displacement of spring from its equilibrium position.
For stretch spring by 2.0 cm or 0.02 m, we need 8.0 J of energy. Hence, substitute the suitable values in equation (1).

k = 4 x 10⁴ N/m
Energy needed to stretch a spring by 6.0 cm can be determine by the equation (1).
Substitute 0.06 m for x and 4 x 10⁴ N/m for k in equation (1).

E = 72 J
But we already have 8.0 J. So, the extra energy needed to stretch spring by additional 4 cm is :
E = ( 72 - 8 ) J = 64 J
Answer:
Option D
Explanation:
Resistors are said to be connected in “Series”, when they are daisy chained together in a single line. Since all the current flowing through the first resistor has no other way to go it must also pass through the second resistor and the third and so on. Then, resistors in series have a Common Current flowing through them as the current that flows through one resistor must also flow through the others as it can only take one path.
Total Resistance = R₁ + R₂ +R₃ +R₄ ohm
Note then that the total or equivalent resistance, R has the same effect on the circuit as the original combination of resistors as it is the algebraic sum of the individual resistances.
Total resistance R = 3 + 3 + 3 +3
= 12 ohm
Work:
1 kilometer = 1000 meters
45 × 60 = 2700
W = F × D
W = 2,000 N × 1,000 m
W = 2,000,000 J
P = W ÷ t
P = 2,000,000 J ÷ 2,700 s
P = 741 watts
Answer:
741 watts of horse power.