The force needed to overcome sliding friction is more than the force needed to overcome rolling friction or static or even fluid
The addition of vectors involve both magnitude and direction. In this case, we make use of a triangle to visualize the problem. The length of two sides were given while the measure of the angle between the two sides can be derived. We then assign variables for each of the given quantities.
Let:
b = length of one side = 8 m
c = length of one side = 6 m
A = angle between b and c = 90°-25° = 75°
We then use the cosine law to find the length of the unknown side. The cosine law results to the formula: a^2 = b^2 + c^2 -2*b*c*cos(A). Substituting the values, we then have: a = sqrt[(8)^2 + (6)^2 -2(8)(6)cos(75°)]. Finally, we have a = 8.6691 m.
Next, we make use of the sine law to get the angle, B, which is opposite to the side B. The sine law results to the formula: sin(A)/a = sin(B)/b and consequently, sin(75)/8.6691 = sin(B)/8. We then get B = 63.0464°. However, the direction of the resultant vector is given by the angle Θ which is Θ = 90° - 63.0464° = 26.9536°.
In summary, the resultant vector has a magnitude of 8.6691 m and it makes an angle equal to 26.9536° with the x-axis.
Answer:
x = 1.00486 m
Explanation:
The complete question is:
" The potential energy between two atoms in a particular molecule has the form U(x) =(2.6)/x^8 −(5.1)/x^4 where the units of x are length and the num- bers 2.6 and 5.1 have appropriate units so that U(x) has units of energy. What is the equilibrium separation of the atoms (that is the distance at which the force between the atoms is zero)? "
Solution:
- The correlation between force F and energy U is given as:
F = - dU / dx
F = - d[(2.6)/x^8 −(5.1)/x^4] / dx
F = 20.8 / x^9 - 20.4 / x^5
- The equilibrium separation distance between atoms is given when Force F is zero:
0 = 20.8 / x^9 - 20.4 / x^5
0 = 20.8 - 20.4*x^4
x^4 = 20.8/20.4
x = ( 20.8/20.4 )^0.25
x = 1.00486 m
The answer is a. nuclear fission is breaking up
