The speed of the rock at 20 m is 34.3 m/s
Explanation:
We can solve this problem by using the law of conservation of energy: the mechanical energy of the rock, sum of its potential energy + its kinetic energy) must be conserved in absence of air resistance. So we can write:
where
:
is the initial potential energy
is the initial kinetic energy
is the final potential energy
is the final kinetic energy
The equation can also be rewritten as follows:
where:
m = 100 kg is the mass of the rock
is the acceleration of gravity
is the initial height
u = 0 is the initial speed (the rock starts at rest)
is the final height of the rock
v is the final speed when h = 20 m
And solving for v, we find:
Learn more about kinetic energy and potential energy here:
brainly.com/question/6536722
brainly.com/question/1198647
brainly.com/question/10770261
#LearnwithBrainly
Answer:
The horizontal distance is 4.823 m
Solution:
As per the question:
Mass of man, m = 65.0 kg
Height of the hill, H = 5.00 m
Mass of the backpack, m' = 20.0 kg
Height of ledge, h = 2 m
Now,
To calculate the horizontal distance from the edge of the ledge:
Making use of the principle of conservation of energy both at the top and bottom of the hill (frictionless), the total mechanical energy will remain conserved.
Now,
where
KE = Kinetic energy
PE = Potential energy
Initially, the man starts, form rest thus the velocity at start will be zero and hence the initial Kinetic energy will also be zero.
Also, the initial potential energy will be converted into the kinetic energy thus the final potential energy will be zero.
Therefore,
where
v = velocity at the hill's bottom
Now,
Making use of the principle of conservation of momentum in order to calculate the velocity after the inclusion, v' of the backpack:
Now, time taken for the fall:
Now, the horizontal distance is given by:
x = v't = 
B. The gravity acceleration is in the same direction as the force of gravity, and thus towards the centre of the earth
Answer:
A) Emin = eV
B) Vo = (E_light - Φ) ÷ e
Explanation:
A)
Energy of electron is the product of electron charge and the applied potential difference.
The energy of an electron in this electric field with potential difference V will be eV. Since this is the least energy that the electron must reach to break out, then the minimum energy required by this electron will be;
Emin = eV
B)
The maximum stopping potential energy is eVo,
The energy of the electron due to the light is E_light.
If the minimum energy electron must posses is Φ, then the minimum energy electron must have to reach the detectors will be equal to the energy of the light minus the maximum stopping potential energy
Φ = E_light - eVo
Therefore,
eVo = E_light - Φ
Vo = (E_light - Φ) ÷ e
The answer is false. The speed of the astronaut cancels out the force of gravity, causing a 'stationary freefall'. While under these effects, it is not required for an astronaut to 'strengthen' his body.
