Answer:
1.28 m
Explanation:
Given;
Radius, r = 1.5 cm = 0.015 m
Time, t = 19 s
Average angular speed = 4.5 rad/s
Consider a point when the tape is moving at a constant velocity along the circumference of the circular reel of radius r. The linear velocity v at this point is given by;
v = rω ----(1)
Where
v is the linear velocity of the circular motion
r is the radius of the reel
ω is the the angular velocity.
At a point the tap undergoes a linear motion before passing round the reel of the cassette. The linear velocity v at this point is given by;
v = L/t ----(2)
where;
v is the velocity of the linear motion
L is the length of the tape (distance covered by the tape)
t is the time taken
Equating equation(1) and equation (2)
L/t = rω
L = rωt
Substituting the given values,
L = 0.015 × 4.5 × 19
L = 1.2825 m
L = 1.28 m
Answer:
I. They come from sources across space
II. They travel in a straight line from their source.
III. They can be reflected by some types of material.
Explanation:
Light wave can be defined as an electromagnetic wave that do not require a medium of propagation for it to travel through a vacuum of space where no particles exist.
The following statements about light waves are true;
I. They come from sources across space.
II. They travel in a straight line from their source.
III. They can be reflected by some types of material. reflection occurs when a ray of light or wavefronts bounces off a smooth surface. Thus, when light hit a surface, it bounces back to the medium from which it was originally propagated with.
However, light waves cannot travel through all type of material except materials that are transparent or translucent but not opaque.
Impulse
it’s the only one that makes sense energy is just light and power almost the same thing
Refer to the diagram shown below.
The initial KE (kinetic energy) of the system is
KE₁ = (1/2)mu²
After an inelastic collision, the two masses stick together.
Conservation of momentum requires that
m*u = 2m*v
Therefore
v = u/2
The final KE is
KE₂ = (1/2)(2m)v²
= m(u/2)²
= (1/4)mu²
= (1/2) KE₁
The loss in KE is
KE₁ - KE₂ = (1/2) KE₁.
Conservation of energy requires that the loss in KE be accounted for as thermal energy.
Answer: 1/2
Answer:
371.2 mm
Explanation:
The Balmer series of spectral lines is obtained from the formula
1/λ = R(1/2² -1/n²) where λ = wavelength, R = Rydberg's constant = 1.097 × 10⁷ m⁻¹
when n = 15
1/λ = 1.097 × 10⁷ m⁻¹(1/2² -1/15²)
= 1.097 × 10⁷ m⁻¹(1/4 -1/225)
= 1.097 × 10⁷ m⁻¹(0.25 - 0.0044)
= 1.097 × 10⁷ m⁻¹ 0.245556
= 2.693 10⁶ m⁻¹
So,
λ = 1/2.693 10⁶ m⁻¹
= 0.3712 10⁻⁶ m
= 371.2 mm
