Answer:
.
Explanation:
Let
denote the absolute temperature of this object.
Calculate the value of
before and after heating:
.
.
By the Stefan-Boltzmann Law, the energy that this object emits (over all frequencies) would be proportional to
.
Ratio between the absolute temperature of this object before and after heating:
.
Therefore, by the Stefan-Boltzmann Law, the ratio between the energy that this object emits before and after heating would be:
.
Answer:
I should be active for 15 hours to meet the physical activity requirement.
Explanation:
Since time dilates in moving objects, we use the formula t = t₀/√(1 - β²) where t = time in space vehicle, t₀ = time on earth = 9 hours and β = v/c where v = speed of space vehicle = 0.8c.
So, t = t₀/√(1 - β²)
t = 9/√(1 - (v/c)²)
= 9/√(1 - (0.8c/c)²)
= 9/√(1 - (0.8)²)
= 9/√(1 - (0.64)
= 9/√0.36
= 9/0.6
= 15 hr
So, according to a timer on the space vehicle, I should be active for 15 hours to meet the physical activity requirement.
Answer:
The same amount of energy is required to either stretch or compress the spring.
Explanation:
The amount of energy required to stretch or compress a spring is equal to the elastic potential energy stored by the spring:

where
k is the spring constant
is the stretch/compression of the spring
In the first case, the spring is stretched from x=0 to x=d, so

and the amount of energy required is

In the second case, the spring is compressed from x=0 to x=-d, so

and the amount of energy required is

so we see that the amount of energy required is the same.
Mmm tricky.
Since the velocity is constant, I'm going to assume there is no acceleration in any direction. This means there is no net force in the I or J forection!
Since there are 2 forces, both must be equal and opposite in direction to perfectly cancel each other out.
So the opposite of F1 is (-2N)I + (6N)J!
Answer: 0.683
Explanation: The relationship between a car moving along a curve and the frictional force is given below as
us×g = v²/r
Where us = coefficient of static friction =?, g = acceleration due to gravity = 9.8 m/s², v = 22.4 m/s and r = 75m
By substituting the parameters, we have that
us×9.8 = 22.4²/ 75
us ×9.8 = 501.76/75
us ×9.8 = 6.690
us = 6.690/9.8 = 0.683