Answer:
Efficiency = 52%
Explanation:
Given:
First stage
heat absorbed, Q₁ at temperature T₁ = 500 K
Heat released, Q₂ at temperature T₂ = 430 K
and the work done is W₁
Second stage
Heat released, Q₂ at temperature T₂ = 430 K
Heat released, Q₃ at temperature T₃ = 240 K
and the work done is W₂
Total work done, W = W₁ + W₂
Now,
The efficiency is given as:
or
Work done = change in heat
thus,
W₁ = Q₁ - Q₂
W₂ = Q₂ - Q₃
Thus,
or
or
also,
or
thus,
thus,
or
or
Efficiency = 52%
That's true. The only way to stop an object from radiating energy
is to cool it to absolute zero. Since the temperature of space is
roughly 3 degrees above absolute zero, the atoms or molecules
of every object have some kinetic energy, and the object radiates
some heat.
Of course it also absorbs heat at the same time, mostly from the
huge number of stars shining on it.
Answer:
A) The ball will roll forever in a straight path.
Answer:
θ₁ = 0.5 revolution
Explanation:
We will use the conservation of angular momentum as follows:
where,
I₁ = initial moment of inertia = 18 kg.m²
I₂ = Final moment of inertia = 3.6 kg.m²
ω₁ = initial angular velocity = ?
ω₂ = Final Angular velocity = 
= 1.67 rev/s
Therefore,
where,
θ₁ = revolutions if she had not tucked at all = ?
t₁ = time = 1.5 s
Therefore,
<u>θ₁ = 0.5 revolution</u>
how does a pedometer help people reach their fitness goals?
a. It measures calories burned.
b. It usually doubles as an MP3 player and keeps people motivated.
c. They count steps during a workout.
d. They measure the number of lifts done per exercise.
