Answer:
kinetic friction may be greater than 400 N or smaller than 400 N
Explanation:
As we know that maximum value of static friction on the rough surface is known as limiting friction and the formula of this limiting friction is known as

now when object is sliding on the rough surface then the friction force on that surface is known as kinetic friction and the formula of kinetic friction is known as

now we know that

so here value of limiting static friction force is always more than kinetic friction
also we know that
initially when body is at rest then static friction value will lie from 0 N to maximum limiting friction
and hence kinetic friction may be greater than static friction or if the static friction is maximum limiting friction then kinetic friction is smaller than static friction
so kinetic friction may be greater than 400 N or smaller than 400 N
The answer is either C or D..
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Answer:



Explanation:
By analyzing the torque on the wheel we get:
Solving for T: 
On the object:
Replacing our previous value for T:

The relation between angular and linear acceleration is:

So,

Solving for α:

The linear acceleration will be:

And finally, the tension will be:

These are the values of all the variables: α, a, T
Answer:

Explanation:
assume
M= mass of Mars
m=mass of phobos
r=orbital radius
T=period
we can apply F=ma to this orbital motion (considering the cricular motion laws)
where,
and a=rω^2
where ω=
and G is the universal gravitational constant.
G = 6.67 x 10-11 N m2 / kg2
