(a) 1800 N
The equation of the forces along the vertical direction is:

where
is the component of the applied force along the vertical direction
N is the normal force on the sled
mg is the weight of the sled
Substituting:
F = 1210 N
m = 246 kg

We find N:

(b) 0.580
The equation of the forces along the horizontal direction is:

where
is the horizontal component of the push applied by the mule
is the static frictional force
Substituting:
F = 1210 N
N = 1800 N

We find
, the coefficient of static friction:

(c) 522 N
In this case, the force exerted by the mule is

So now the equation of the forces along the horizontal direction can be written as

where

and
is the new frictional force, which is different from part (b) (because the value of the force of friction ranges from zero to the maximum value
, depending on how much force is applied in the opposite direction)
Solving the equation,

Answer:

Explanation:
We are given that
Mass,
Radius,r=0.8 m

Height,h=2.9 m
We have to find the angular acceleration of the cylinder.
According to question


Where



Substitute the value


Where 


Angular acceleration,
Answer:
Explanation:
A ) The spheres are non conducting , charge will not move on the surface so neutralization of charge by + ve and - ve charge is not possible. Charges will remain intact on them . The electric field inside them will be zero . Electric field outside shell will not be spherically symmetrical . Lines of force will emanate from the surface of positively charged shell outwardly oriented and end at negatively charged shell .
B )
distance between the centres of spherical shell
= 2 a
potential energy of charges
= k q₁ x q₂ / R
= k x - Q x Q / ( 2a )
= - k Q²/ 2a
So work needed to separate them to infinity will be equal to
= k Q²/ 2a
The statement above is true. The phase of matter which is exposed to normal atmospheric pressure is indeed solely dependent upon temperature. If the matter is exposed to the normal atm pressure, its temperature depends on it.