To solve this problem we will apply the concept related to the kinetic energy theorem. Said theorem states that the work done by the net force (sum of all forces) applied to a particle is equal to the change experienced by the kinetic energy of that particle. This is:


Here,
m = mass
v = Velocity
Our values are given as,


Replacing,


Therefore the mechanical energy lost due to friction acting on the runner is 907J
Answer:
Although the wave slows down, its frequency remains the same, due to the fact that its wavelength is shorter. When waves travel from one medium to another the frequency never changes.
Normal reaction force on the block while it is at rest on the inclined plane is given as

here we know that
m = 46 kg

now we will have

now the limiting friction or maximum value of static friction on the block will be given as


Above value is the maximum value of force at which block will not slide
Now the weight of the block which is parallel to inclined plane is given as

here we know that

Now since the weight of the block here is less than the value of limiting friction force and also the block is at rest then the frictional force on the block is static friction and it will just counter balance the weight of the block along the inclined plane.
So here <u>friction force on the given block will be same as its component on weight which is 218.55 N</u>
Answer:
38.87 m/s
Explanation:
Given that the ball is dropped from a height = 77 m
u = 0 m/s
s = 77 m
a = g = 9.81 m/s²
Applying the expression as:

Applying values as:

<u>The speed with which the ball hit the ground = 38.87 m/s</u>