Answer:
Explanation:
Given
weight of block 
A force is of
is applied on the block
As 1 N is less than weight of block so block exert Force less than its weight


So Block exert a force of 2 N downward on floor
Answer:
Explanation:
mass of backpack, m = 8.1 kg
weight of climber, W = 656 N
height raised, h = 9.4 m
time, t = 28.2 min = 28.2 x 60 = 1692 second
weight of backpack, w = m x g = 8.1 x 9.8 = 79.38 N
Work done by the climber on the backpack = mg x h = 79.38 x 9.4 = 746.17 J
Wok done in lifting herself + backpack = (W + w) x h
= (656 + 79.38) x 9.4 = 6912.57 J
Power developed by the climber,P = Total work / time
P = 6912.57 / 1692 = 4.09 W
<u>Given data</u>
Determine Internal energy of gas N₂, (U) = ?
Temperature (T) = 25° C
= 25+273 = 298 K,
Gas constant (R) = 8.31 J/ mol-K ,
Number of moles (n) = 3 moles,
<u>Internal energy of N₂ </u>
Internal energy is a property of thermodynamics, the concept of internal energy can be understand by ideal gas. For example N₂, the observations for oxygen and nitrogen at atmospheric temperatures, f=5, (where f is translational degrees of freedom).
So per kilogram of gas,
The internal energy (U) = 5/2 .n.R.T
= (5/2) × 3 × 8.31 ×298
= 18572.85 J
<em>The internal energy of the N₂ is 18,572.85 J and it is approximately equal to 18,600 J given in the option B.</em>
Answer:
According to the answer, the speed of light is being achieved.
Explanation:
The velocity of the light is:

Where E = energy = 3.03x10⁻¹⁹J
P = momentum = 1.01x10⁻²⁷kgm/s
Replacing:

The energy required by the excitation of the line is:
ΔE = hν = hc / λ
where:
ΔE = energy difference
h = Planck constant
ν = line frequency
c = speed of light
λ = line wavelength
The energy difference must be supplied by the electron, supposing it transfers all its kinetic energy to excite the line:

Therefore,

And solving for v we get:

Plugging in numbers (after trasforing into the correct SI units of measurement):

=9.4 · 10⁵ m/s
Hence, the electron must have a speed of
9.4 · 10<span>
⁵ m/s in order to excite the <span>492nm</span> line.</span>