During freezing, energy is released by the mass of water without change in temperature. Such energy will also be required if the same mass of water has to be melted.
Then,
Number of moles = mass/molar mass = 253/18.02 =14.04 moles
Energy released = moles*molar enthalpy of fusion = 14.04*6.008 = 84.35 kJ
Answer:
The total frictional force is 358.0 newtons
Explanation:
Power is the amount of average work (W) an object does on a period of time (Δt):

Remember average work is average force (F) times displacement (Δs):

but displacement over time is average speed
, then:
(1)
That is, the power of the car is the force the engine does times the speed of the car. As the question states, if the car is at constant velocity then the power developed is used to overcome the frictional forces exerted by the air and the road, that is by Newton's first law, the force the motor of the car does is equal the force of frictional forces. So, to find the frictional forces we only have to solve (1) for F:

Knowing that 1hp is 746W then 30hp=22380W and 1 mile = 1609m then 140 mph = 225308
=
, then:

Answer:
<h2>45.68 g</h2>
Explanation:
Given 45.678 g, converting the value to 4 digits is similar to converting the decimal number to 4 significant figure. We can see that the decimal number initially contains 5 numbers. To covert to a 4 digits number we will convert the last digit which is 8 to 0 because 0 is insignificant.
If the number we are converting to zero is more than 4 then the preceding number (7) will be rounded up by adding 1 to it
The decimal number will become 45.68.
Note that the value of 7 was rounded up to 8 since the value we are converting to zero is more than 4.
<em>Hence the decimal value in 4 digits is 45.68 g</em>
Answer:
43.41 mm
Explanation:
Given:
thickness of sheet, t = 6 mm
Force exerted by punch, F = 45 KN
Average shearing stress, T = 55 MPa
From average shearing stress T = Force F / Area A
Hence area = force/stress =45000/ 55 =
From area = pi*diameter*thickness
diameter = area/(pi* thickness)
= 818.18/(3.142*6)
= 43.41 mm