You oughtta be able to do this one.
The "efficiency" is just the portion of the input work that
comes out in a useful form.
If the efficiency is 70%, that tells you that however much work
you put INto the machine, the machine will do 70% of that much
work for you at the output side.
Put 20,000 J in ... out comes (0.70) x (20,000 J) = 14,000 J .
What happens to the other 30% of the work you put into it ?
It turns into HEAT. That's why machines always have to be
cooled somehow while they're running.
Answer:
Explanation:
This is a problem based on time dilation , a theory given by Albert Einstein .
The formula of time dilation is as follows .
t₁ = 
t is time measured on the earth and t₁ is time measured by man on ship .
A ) Given t = 20 years , t₁ = ? v = .4c

=1.09 x 20
t₁= 21.82 years
B ) Given t = 5 years , t₁ = ? v = .2c

=1.02 x 5
t₁= 5.1 years
C ) Given t = 10 years , t₁ = ? v = .8c

=1.67 x 10
t₁= 16.7 years
D ) Given t = 10 years , t₁ = ? v = .4c

=1.09 x 10
t₁= 10.9 years
E ) Given t = 20 years , t₁ = ? v = .8c

=1.67 x 20
t₁= 33.4 years
The train accelerated continuously, throughout the trip. Six phases of the trip are described in the question. (D)
Answer:
The hollow cylinder rolled up the inclined plane by 1.91 m
Explanation:
From the principle of conservation of mechanical energy, total kinetic energy = total potential energy

The total energy at the bottom of the inclined plane = total energy at the top of the inclined plane.

moment of inertia, I, of a hollow cylinder = ¹/₂mr²
substitute for I in the equation above;


given;
v₁ = 5.0 m/s
vf = 0
g = 9.8 m/s²

Therefore, the hollow cylinder rolled up the inclined plane by 1.91 m