All you have to do is get the culmative effect of the forces by predicting the direction in which each object will move. Just write down what you know and put down questions for your teacher.
Answer:
The electric force between them if the pieces of grain are 2 cm apart is 
.
Explanation:
Given:
Charge on one grain, 
Charge on another grain, 
Separation between them, 
Electric force acting between two charges 
separated by a distance 
is given as:
Where, 
is Coulomb's constant equal to 
.
Now, plug in all the values and solve for 
.
Therefore, the electric force between them if the pieces of grain are 2 cm apart is .
Answer:
Explanation:
Comment
You have to read this carefully enough that you don't mix up energy and forces.
Gravity is a force. If you don't believe me try jumping off a building. Which way are you going to go and why? Down because gravity attracts your mass.
So Magnetism must be a force as well. It acts in one direction, but not a specific one the way gravity acts). It also either attracts or repulses (pushes an object away)
Answer A
Answer:
0.001152m
Explanation:
Linear expansivity of a material is the change in length of the material per unit length per degree rise in temperature. Mathematically,
¢ = ∆L/L1∆°C
¢ is the linear expansivity of the material = 12 x 10⁻⁶ °C⁻¹
Where ∆L is the change in length = L2-L1
L2 is the final length = ?
L1 is the initial length = 12m
∆°C is the change in temperature = °C2 - °C1 = 50-(-30) = 80°C
Substituting this values inside the formula to get the final length L2 after expansion, we have;
12 x 10⁻⁶ °C⁻¹ = L2-12/12×80
12 x 10⁻⁶ °C⁻¹ = L2-12/960
L2-12= 960×12 x 10⁻⁶ °C⁻¹
L2-12 = 0.001152
L2 = 12+0.001152
L2 = 12.001152m
Expansion will be the change in length L2-L1 = 12.001152-12
= 0.001152m
The expansion cracks between the slabs should be 0.001152m wide to prevent buckling
Answer:
k_max = 31.82 w/mk
k_min = 17.70 w/mk
Explanation:
a) the maximum thermal conductivity is given as
where k_m is thermal conductvitiy of metal
k_p is thermal conductvitiy of carbide
v_m = proportion of metal in the cement = 0.17
v_p = proportion of carbide in the cement = 0.83
= 66*0.17 + 28*0.83
k_max = 31.82 w/mk
b) the minimum thermal conductivity is given as
= \frac{28+66}{28*0.17 +66*0.83}
k_min = 17.70 w/mk
