Answer:
y = 67.6 feet, y = 114.4/ (22 - 3t)
Explanation:
For this exercise let's use that light travels in a straight line and some trigonometric relationships, the symbols are in the attached diagram
Large triangle Projector up to the screen
tan θ = y / L
For the small triangle. Projector up to the person
tan θ = y₀ / (L-d)
The angle is the same, so we equate the two equations
y₀ / (L -d) = y / L
y = y₀ L / (L-d)
The distance from the screen (d), we look for it with kinematics
v = d / t
d = v t
we replace
y = y₀ L / (L - v t)
y = 5.2 22 / (22 - 3 t)
y = 114.4 (22 - 3t)⁻¹
This is the equation of the shadow height change as a function of time
For the suggested distance the shadow has a height of
y = 114.4 / (22-13)
y = 67.6 feet
Ionic bonds with electrostatic attractions
Answer: 75V
Explanation:
Given that,
total resistance (Rtotal) = 150Ω
Current (I) = 0.5A
Change in electric potential (V) = ?
Recall that potential difference is the product of amount of current and the amount of resistance in the circuit. And its unit is volts.
So, apply the formula V = I x Rtotal
V = 0.5A x 150Ω
V = 75V
Thus, the change in electric potential across the circuit is 75 Volts
a) KE=0.5*mv^2==0.5*145*25^2=45312.5 J
b) PE=mgh=145*9.8*3.5=4973.5 J
c) ME=KE+PE=m(0.5v^2+gh)=62524 J