Right, as you mentioned in the comments, you find 
by plugging in the different values of 
.
For 
, we have
Similarly, for 
, you get
Answer:
E = 2,964 10⁻¹⁹ J
Explanation:
The energy of the photons is given by the Planck relation
E = h f
the speed of light is related to wavelength and frequency
c = λ f
we substitute
E = h c /λ
let's reduce the magnitude to the SI system
λ = 671 nm = 671 10⁻⁹ m
let's calculate
E = 6.63 10⁻³⁴ 3 10⁸ /671 10⁻⁹
E = 2,964 10⁻¹⁹ J
Answer:
Option C - 39.2 J
Explanation:
We are given that;
Mass; m = 2 kg.
Distance moved off the floor;d = 10 m.
Acceleration due to gravity;g = 9.8 m/s².
We want to find the work done.
Now, the Formula for work done is given by;
Work = Force × displacement.
In this case, it's force of gravity to lift up the boots, thus;
Formula for this force is;
Force = mass x acceleration due to gravity
Force = 2 × 9.8 = 19.2 N
∴ Work done = 19.6 × 2
Work done = 39.2 J.
Hence, the Work done to life the boot of 2 kg to a height of 2 m is 39.2 J.
I'm gonna have to assume the girl is on the right side and boy on left.
The net force is the sum of all forces on an object (includes negatives).
Let's say the force of the boy is variable <em>b</em>. Use the formula F = ma.
<em>b </em>+ 3.5 = 0.2(2.5)
This is now simple algebra. Solve to get that <em />the boty is exerting a force of -3N to the left.
