Answer:
65 m/s
Explanation:
v=v0+at <=> v = 11 + 12 t ∧ t = 4.5 s <=> v = 11 + 12×4.5 <=> v = 65 m/s
First
let us imagine the projectile launched at initial velocity V and at angle
θ relative to the horizontal. (ignore wind resistance)
Vertical component y:
The
initial vertical velocity is given as Vsinθ
The moment the projectile reaches the maximum
height of h, the vertical velocity
will be 0, therefore the time t taken to attain this maximum height is:
h = Vsinθ - gt
0 = Vsinθ - gt
t = (Vsinθ)/g
where
g is acceleration due to gravity
Horizontal component x:
The initial horizontal velocity is given as Vcosθ. However unlike
the vertical component, this horizontal velocity remains constant because this is unaffected by gravity. The time to travel the
horizontal distance D is twice the value of t times the horizontal velocity.
D = Vcosθ*[(2Vsinθ)/g]
D = (2V²sinθ cosθ)/g
D = (V²sin2θ)/g
In order for D (horizontal distance) to be
maximum, dD/dθ = 0
That is,
2V^2 cos2θ / g = 0
And since 2V^2/g must not be equal to zero, therefore cos(2θ) = 0
This is true when 2θ = π/2 or θ = π/4
Therefore it is now<span> shown that the maximum horizontal travelled is attained when
the launch angle is π/4 radians, or 45°.</span>
Answer:
The work done by gravity during the roll is 490.6 J
Explanation:
The work (W) is:

<em>Where</em>:
F: is the force
d: is the displacement = 20 m
The force is equal to the weight (W) in the x component:

<em>Where:</em>
m: is the mass of the bowling ball = 5 kg
g: is the gravity = 9.81 m/s²
θ: is the degree angle to the horizontal = 30°
Now, we can find the work:
Therefore, the work done by gravity during the roll is 490.6 J.
I hope it helps you!
Answer:I=12 A
Explanation:
Given
Resistance 
Voltage 
According to ohm's law current through a conductor is directly proportional to the voltage applied.


where V=Voltage
I=Current
R=resistance



1. Frequency: 
The energy given is the energy per mole of particles:

1 mole contains a number of Avogadro of particles,
, equal to
particles
So, by setting the following proportion, we can calculate the energy of a single photon:

This is the energy of a single photon; now we can calculate its frequency by using the formula:

where
is the Planck's constant
f is the photon frequency
Solving for f, we find

2. Wavelength: 
The wavelength of the photon is given by the equation:

where

is the speed of the photon (the speed of light). Substituting,
