Answer:
The kinetic energy of the particle will be 12U₀
Explanation:
Given that,
A particle is launched from point B with an initial velocity and reaches point A having gained U₀ joules of kinetic energy.
Constant force = 12F
According to question,
The kinetic energy is
....(I)
Constant force = 12F
A resistive force field is now set up ,
Resistive force is given by,

When the particle moves from point B to point A then,
We need to calculate the kinetic energy
Using formula for kinetic energy

Put the value of 

Now, from equation (I)

Hence, The kinetic energy of the particle will be 12U₀.
Answer:
Option (D) : The object slows down.
Answer:
The distance is
=
7
m
Explanation:
Apply the equation of motion
s
(
t
)
=
u
t
+
1
2
a
t
2
The initial velocity is
u
=
0
m
s
−
1
The acceleration is
a
=
2
m
s
−
2
Therefore, when
t
=
3
s
, we get
s
(
3
)
=
0
+
1
2
⋅
2
⋅
3
2
=
9
m
and when
t
=
4
s
s
(
4
)
=
0
+
1
2
⋅
2
⋅
4
2
=
16
m
Therefore,
The distance travelled in the fourth second is
d
=
s
(
4
)
−
s
(
3
)
=
16
−
9
=
7
m
The answer for the following problem is explained below.
Therefore the volume charge density of a substance (ρ) is 0.04 ×
C.
Explanation:
Given:
radius (r) =2.1 cm = 2.1 ×
m
height (h) =8.8 cm = 8.8 ×
m
total charge (q) =6.1×
C
To solve:
volume charge density (ρ)
We know;
<u> ρ =q ÷ v</u>
volume of cylinder = π ×r × r × h
volume of cylinder =3.14 × 2.1 × 2.1 ×
× 8.8 ×
volume of cylinder (v) = 122.23 ×
<u> ρ =q ÷ v</u>
ρ = 6.1×
÷ 122.23 ×
<u>ρ = 0.04 × </u>
<u> C</u>
Therefore the volume charge density of a substance (ρ) is 0.04 ×
C.