I would say its c . <span>National Academy of Forensic Science</span>
6. 0N. This questions requires understanding of how friction functions. Friction is a resistive force, meaning it opposes the direction of any applied or unbalanced forces. The box in the question experiences no horizontal force, so there is no resistive force in response to it, making it 0N.
7. This question tests your understanding of static friction. Static friction only applies when an applied or unbalanced force is applied to an object which does not move. The static friction always equals the magnitude of the applied or unbalanced force component parallel to the surface which the object rests on. The question states that the crate starts to move only when the applied force exceeds 313N, so we use this value to determine the force of static friction. The additional info in the question pertaining to when the crate is moving is irrelevant when determining static friction (only relevant if determining kinetic friction). Knowing this we solve for the weight of the crate:
F = mg
F = (45)(9.8)
F = 441N = Normal Force
The weight of the crate is also equal to the Normal Force since the object rests on a horizontal surface and the applied force is horizontal as well. In this question, since the object is not moving at 313N of applied force, the magnitude of static friction equals the applied force:
Ff = μs * Fn
(313) = μs (441)
0.71 (rounded) = μs
Answer
given,
copper rod length = 50 cm
density of the copper = 8.92 g/cm³
iron rod length = 50 cm
density of iron = 7.86 g/cm³
mass of iron = density × volume
m_i = 7.86 × A × l/2
m_c = 8.96 × A × l/2
taking the intersection of copper and iron rod be starting point cooper side is taken as positive side and iron side length is taken to be -ve side.
center of mass
= 
= 
= 
= 
= 0.015793 m
= 1.579 m (+ve)
center of mass shift to cooper because cooper is heavy.
<span>A wave has a speed of 50m/sec. If its frequency is 100 hz, what's it's wavelength?</span>
