How much heat is necessary to supply 2 kilograms of aluminum to raise its temperature by 20 ° C?
Answer:
36000J
Explanation:
Given parameters:
Mass of aluminum = 2kg = 2000g
Temperature rise = 20°C
Unknown:
Amount of heat needed for the temperature change = ?
Solution:
The amount of heat needed to cause this temperature rise is given as;
H = m c (T₂ - T₁)
H is the amount of heat
m is the mass
c is the specific heat of aluminum = 0.9J/g°C
Insert the parameters and solve;
H = 2000 x 0.9 x 20 = 36000J
Force = mass × acceleration
static force = coefficient of friction × normal force
1.70 = 0.0600 × normal force...
normal force = 1.70 ÷ 0.0600.. to obtain....
The answer is 59
the atomic mass is the number at the bottom so you've gotta round it to the nearest whole number<span />
. The energy of shells in a hydrogen atom is calculated by the formula E = -Eo/n^2 where n is any integer, and Eo = 2.179X10^-18 J. So, the energy of a ground state electron in hydrogen is:
E = -2.179X10^-18 J / 1^2 = -2.179X10^-21 kJ
Consequently, to ionize this electron would require the input of 2.179X10^-21 kJ
2. The wavelength of a photon with this energy would be:
Energy = hc/wavelength
wavelength = hc/energy
wavelength = 6.626X10^-34 Js (2.998X10^8 m/s) / 2.179X10^-18 J = 9.116X10^-8 m
Converting to nanometers gives: 91.16 nm
3. Repeat the calculation in 1, but using n=5.
4. Repeat the calculation in 2 using the energy calculated in 3.
