# An object with a mass of # 25 kg# is lying still on a surface and is compressing a horizontal spring by #5/2 m#. If the spring's constant is # 4 (kg)/s^2#, what is the minimum value of the surface's coefficient of static friction?

##### 2 Answers

Jan 21, 2016

#### Answer:

I found

#### Explanation:

Have a look:

Jan 21, 2016

#### Answer:

#### Explanation:

Take a look at the figure ignore d(t) we will not need it

Now put free body diagram we will have the following equations

#W = N# #F_k =kx = F_f #

Where,

#W = mg#

N = Normal force;

#F_k# = spring force

#F_f# = frictional force

now#F_f = muN#

But#N = mg#

So,#mumg = kx# substitute and get

# mu = (kx)/(mg)#

#mu = 2/49#