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
In this problem we have the electric field intensity E:
E = 6.5 ×
newtons/coulomb
We have the magnitude of the load:
q = 6.4 ×
coulombs
We also have the distance d that the load moved in a direction parallel to the field 1.2 ×
meters.
We know that the electric potential energy (PE) is:
PE = qEd
So:
PE = (6.4 ×
)(6.5 ×
)(1.2 ×
)
PE = 5.0 x
joules
None of the options shown is correct.
Potential energy is energy stored in an object. kinetic energy is energy of motion
Answer:
a)KE=878.8 J
b)W=2636.4 J
Explanation:
Given that
mass ,m = 65 kg
Initial speed ,u = 5.2 m/s
a)
We know that kinetic energy KE is given as follows

m=mass
u=velocity
Now by putting the values in the above equation we get

KE=878.8 J
b)
We know that
Work done by all forces = Change in the kinetic energy
The final velocity , v= 2 u = 2 x 5.2 m/s
v= 10.4 m/s

Now by putting the values in the above equation we get

W=2636.4 J
a)KE=878.8 J
b)W=2636.4 J
Density
is a value for mass, such as kg, divided by a value for volume, such as m3.
Density is a physical property of a substance that represents the mass of that
substance per unit volume. It is a property that can be used to describe a
substance.<span> </span><span>It has standard units of
kg/m^3 or g/mL.
So, the best answer is option C.</span>