Answer:
The velocity of the observer is 6.8 m/s
Explanation:
Doppler effect equation is given by the formula:
The velocity of the observer is 6.8 m/s
When sedimentary rock is exposed to heat and pressure it changes into METAMORPHIC ROCK.
Heat and pressure have the capacity to change a rock into a completely new type of rock. An igneous rock or a sedimentary rock can be changed into a metamorphic rock as a result of heat and pressure which the rock is subjected to. Metamorphic rocks are usually formed from already existing rocks that are exposed to pressure and heat.
Answer:
Explanation:
Let a be the acceleration of launch. In 10 seconds , Distance gone up in 10 seconds
s = 1/2at²
= .5 x a x 100
=50a
Velocity after 10 s
u = at = 10a
Now 50a distance in downward direction is travelled in 20 s with initial velocity 10a in upward direction.
s = ut + 1/2 gt²
50a = -10ax20 + .5 x 10x400
250a = 2000
a = 8 m s⁻² .
Velocity after 10 s
= at = 80 m/s
further height reached with this speed under free fall
h = v² / 2g
= 80 x 80 / 2 x 10
= 320 m
height achieved under acceleration
= 50a
= 50 x 8 = 400m
Total height
= 320 + 400= 720 m
velocity after falling from 720 m
v² = 2gh = 2 x10 x 720
v = 120 m/s
Answer:
The change of energy is 60J
Explanation:
We have a closed system, which receives 80 J of energy. It means this energy is entering the system. And also we have 20 J that is dissipating in the shape of heat.
Therefore the amount remaining in the system will be 80 - 20 = 60 J
(a) -1620.8 J
The initial kinetic energy of the skateboarder is:
where m is the skateboarder's mass and u his initial speed;
While the final kinetic energy is
where v is his final speed.
So the change in kinetic energy is
According to the work-energy theorem, the change in mechanical energy (kinetic+potential) of the skateboarder is equal to the work done on it:
where
is the work done by the skateboarder on himself
is the work done by friction
is the change in gravitational potential energy
Solving for 
,
(b) 2.97 m
The change in potential energy of the skateboarder can be written as
where
m = 55.6 kg is the mass
g = 9.8 m/s^2 is the acceleration of gravity
is the change in vertical height of the skateboarder
Solving for ,
Where the negative sign means the skateboarder has moved downwards. Since we are interested only in the absolute value, the answer is
h = 2.97 m
