Answer:
a = 5.53 g , a = -15g
Explanation:
This is an exercise in kinematics.
a) Let's look for the acceleration
as part of rest v₀ = 0
v = v₀ + a t
a = v / t
a = 282 / 5.2
a = 54.23 m / s²
in relation to the acceleration of gravity
a / g = 54.23 / 9.8
a = 5.53 g
b) let's look at the acceleration to stop
va = 0
0 = v₀ -2 a y
a = vi / y
a = 282/2 1
a = 141 m /s²
a / G = 141 / 9.8
a = -15g
Answer:
a)
492 kJ
b)
Consistent
Explanation:
Q = Heat stored by woman from food = 600 k J
η = Efficiency of woman = 18% = 0.18
Q' = heat transferred to the environment
heat transferred to the environment is given as
Q' = (1 - η) Q
Inserting the values
Q' = (1 - 0.18) (600)
Q' = 492 kJ
b)
Yes the amount of heat transfer is consistent. The process of sweating produces the heat and keeps the body warm
A woman climbing the Washington Monument metabolizes food energy with 18% efficiency, meaning 82% of the energy is lost as heat. When we calculate this value, we find that 492 kJ of energy is released as heat, which is consistent with the fact that people quickly warm up when exercising.
The woman climbing the Washington Monument metabolizes 6.00×10² kJ of food energy with an efficiency of 18%. This implies that only 18% of the energy consumed is used for performing work, while the remaining (82%) is lost as heat to the environment.
To calculate the energy lost as heat:
The released heat of 492 kJ is consistent with the fact that a person quickly warms up when exercising, because a significant portion of the body's metabolic energy is lost as heat due to inefficiencies in converting energy from food into work.
#SPJ3
What is the kinetic energy of an electron in a circular orbit around the gold nucleus?
Answer:
a) F = -1.82 10⁻¹⁵ N, b) K = 9.1 10⁻¹⁶ J
Explanation:
a) To calculate the force between the nucleus and the electrons, let's use the Coulomb equation
F = k q Q / r²
as the nucleus occupies a very small volume compared to electrons, we can suppose it as punctual
let's calculate
F = 9 10⁹ (-1.6 10⁻¹⁹) (79 1.6 10⁻¹⁹) / (10⁻¹⁰)²
F = -1.82 10⁻¹⁵ N
b) they ask us for kinetic energy
let's use Newton's second law
F = m a
acceleration is centripetal
a = v² / r
we substitute
F = m v² / r
v = √ (F r / m)
v = √ (1.82 10⁻¹⁵ 10⁻¹⁰ / 9.1 10⁻³¹)
v = √ (0.2 10⁻¹⁶)
v = 0.447 10⁸ m / s
kinetic energy is
K = ½ m v²
K = ½ 9.1 10⁻³¹ (0.447 10⁸)²
K = 0.91 10⁻¹⁵ J
K = 9.1 10⁻¹⁶ J
B. Oceanic crust is made out of much less dense material than continental crust
C. Continental crust is continually renewed through convection in the earth's mantle
D. Continental crust eats oceanic crust for breakfast
Answer:
A. Oceanic crust is continually recycled through convection in the earth's mantle
Explanation:
The oceanic plate is constantly being recycled through the forces of convection within the earth's mantle.
New oceanic plate are formed mid-oceanic ridge for example. As the magma cools and solidifies, they are moved away continually.
This is not the case for the continental curst.
Answer:
s = 6.25 10⁻²² m
Explanation:
Polarizability is the separation of electric charges in a structure, in the case of the atom it is the result of the separation of positive charges in the nucleus and the electrons in their orbits, macroscopically it is approximated by
p = q s
s = p / q
let's calculate
s = 1 10⁻⁴⁰ / 1.6 10⁻¹⁹
s = 0.625 10⁻²¹ m
s = 6.25 10⁻²² m
We see that the result is much smaller than the size of the atom, therefore this simplistic model cannot be taken to an atomic scale.
B) d/√2
C) d/4
D) 2d
E) d/2
Answer:b
Explanation:
Given
Force of attraction is F when charges are d distance apart.
Electrostatic force is given by
where k=constant
and are charges
d=distance between them
In order to double the force i.e. 2F
divide 1 and 2 we get
Answer:
10ms
Explanation:
The bird must travel the length of the train (150m), with a combined speed of 15m/s this means it will take 10s to cross an accumulated 150ms.
Answer:
The time taken by the parrot to cross the train is = 10 m/s
Explanation:
given:
A train of 150 m length is going toward north direction at a speed of 10 m/s
and a parrot is flying towards south direction parallel to the railway track with a speed of 5 m/s
find;
The time taken by the parrot to cross the train
using the distance over speed relation formula t = d / v
where:
v = velocity
d = distance
t = time
v = 10 m/s + 5 m/s = 15 m/s (combine velocity)
d = 150 m
t = ?
plugin values into the formula
t = 150
15
t = 10 m/s
therefore,
The time taken by the parrot to cross the train is = 10 m/s