Question three is C and question 4 is b
Answer:
u = 25 m/s
Explanation:
given,
length of skid = 93 m
coefficient of friction = 0.35
final velocity = 0 m/s
initial velocity = ?
force here is friction f = μ mg
F = ma
now com paring
-μ mg = m a
a = - μ g
a = - 0.35 x 9.8
a = -3.43 m/s²
we know,
v² = u² + 2 a s
0 = u² - 2 x 3.43 x 93
u² = 637.98
u = 25.26 m/s
u = 25 m/s (two significant figure)
Turn your protracted to a 90 degree angle
Answer:
So, insulation essentially works by creating a sort of barrier between the hot and the cold object. This barrier helps to reduce heat transfer by either reflecting the thermal radiation or by decreasing thermal conduction and convection from one object to the other.
Answer:
Approximately 
(assuming that the melting point of ice is 
.)
Explanation:
Convert the unit of mass to kilograms, so as to match the unit of the specific heat capacity of ice and of water.
The energy required comes in three parts:
- Energy required to raise the temperature of that
of ice from 
to (the melting point of ice.) - Energy required to turn of ice into water while temperature stayed constant.
- Energy required to raise the temperature of that newly-formed of water from to
.
The following equation gives the amount of energy 
required to raise the temperature of a sample of mass 
and specific heat capacity 
by 
:
,
where
- is the specific heat capacity of the material,
- is the mass of the sample, and
- is the change in the temperature of this sample.
For the first part of energy input, 
whereas 
. Calculate the change in the temperature:
.
Calculate the energy required to achieve that temperature change:
.
Similarly, for the third part of energy input, 
whereas . Calculate the change in the temperature:
.
Calculate the energy required to achieve that temperature change:
.
The second part of energy input requires a different equation. The energy required to melt a sample of mass and latent heat of fusion 
is:
.
Apply this equation to find the size of the second part of energy input:
.
Find the sum of these three parts of energy:
.
