The formula for working out speed is distance ÷ time.
55 km ÷ 2 hours = 27.5 km/h (average speed for first part of journey)
52km ÷ 5 hours = 10.4 km/h (average speed for second part of journey)
(27.5 + 10.4) ÷ 2 = 18.95 km/h (average speed throughout the journey)
You just multiply these two numbers, it's 1250J
Answer:
#_photons = 30 photons / s
Explanation:
Let's start by finding the energy of a photon of light, let's use 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
E₀ = 6.63 10⁻³⁴ 3 10⁸/500 10⁻⁹
E₀ = 3.978 10⁻¹⁹ J
now let's use a direct proportion rule. If the energy of a photon is Eo, how many fornes has an energy E = 1.2 10⁻¹⁷ J in a second
#_photons = 1 photon (E / Eo)
#_photons = 1 1.2 10⁻¹⁷ /3.978 10⁻¹⁹
#_photons = 3.0 10¹
#_photons = 30 photons / s
Answer:
We kindly invite you to read carefully the explanation and check the image attached below.
Explanation:
According to this problem, the rocket is accelerated uniformly due to thrust during 30 seconds and after that is decelerated due to gravity. The velocity as function of initial velocity, acceleration and time is:
(1)
Where:
- Initial velocity, measured in meters per second.
- Final velocity, measured in meters per second.
- Acceleration, measured in meters per square second.
- Initial time, measured in seconds.
- Final time, measured in seconds.
Now we obtain the kinematic equations for thrust and free fall stages:
Thrust (
,
,
,
)
(2)
Free fall (
,
,
,
)
(3)
Now we created the graph speed-time, which can be seen below.
Answer:
The position of the particle is 6m
The velocity of the particle is 16 m/s in negative direction
The acceleration of the object is -40 m/s²
Explanation:
Given;
motion of the particle along a straight line as x = 6 + 4t² - t⁴
The position of the object when t = 2s
x = 6 + 4(2)² - (2)⁴
x = 6 + 16 - 16
x = 6m
The velocity of the object when t = 2s
Velocity = dx/dt
dx/dt = 8t - 4t³
when t = 2s
Velocity = 8(2) - 4(2)³
Velocity = 16 - 32
Velocity = -16m/s
Velocity = 16 m/s (in negative direction)
The acceleration of the object when t = 2s
Acceleration = d²x/dt² = 8 - 12t²
Acceleration = 8 - 12 (2)²
Acceleration = -40 m/s²