7) 6, i believe, (Cu) 1 atom+ (S) 1 atom+(0)4 atoms.
Answer:
magnitude of force on charge 2Q = 
Direction of force on charge = 61 ⁰
Explanation:
The magnitude on the force on the charge can be evaluated by finding the net force acting on the charge 2Q i.e x-component of the net force and the y-component of the net force
║F║ =
= after considering the forces coming from Q, 3Q and 4Q AND APPLYING COULOMBS LAW
magnitude of force acting on 2Q = 
The direction of the force on charge 2Q is calculated as
tan ∅ =
= 1.8284
therefore ∅ =
1.8284
= 61⁰
Answer
a) Using dimensional analysis we cannot derive the relation, But we can check the correctness of the formula.

now, L H S
s = distance
dimension of distance = [M⁰L¹T⁰]
now, equation on the right hand side
R H S
u = speed
u = m/s
Dimension of speed = [M⁰L¹T⁻¹]
dimension of time
t = sec
Dimension of time = [M⁰L⁰T¹]
Dimension of 'ut' = [M⁰L¹T⁻¹][M⁰L⁰T¹]
= [M⁰L¹T⁰]
now, acceleration= a
a = m /s²
dimension of acceleration = [M⁰L¹T⁻²]
dimension of (at²) = [M⁰L¹T⁻²][M⁰L⁰T¹][M⁰L⁰T¹]
= [M⁰L¹T⁰]
hence, the dimension are balanced.
so, L H S = R H S
b) Moment of inertia of hollow sphere = 
Moment of inertia of solid sphere = 
we know,


Torque is the force that causes rotation
If the same amount of torque is applied to both spheres the sphere with bigger moment of inertia would have smaller angular velocity.
Thus the solid sphere would accelerate more.
Answer:
Coefficient of friction is
.
Work done is
.
Explanation:
Given:
Mass of the box (
):
kg
Force needed (
):
N
The formula to calculate the coefficient of friction between the floor and the box is given by

Here,
is the coefficient of friction and
is the acceleration due to gravity.
Substitute
N for
,
kg for
and
m/s² for
into equation (1) and solve to calculate the value of the coefficient of friction.

The formula to calculate the work done in overcoming the friction is given by

Here,
is the work done and
is the distance travelled.
Substitute
N for
and
for
into equation (2) to calculate the work done.
