The correct answer is (A) 2.0 J
Total energy of the pendulum is the sum of its kinetic and potential energy. At the instant of time, when the pendulum is at a height <em>h</em> and has a speed <em>v, </em>Its energy is given by,

Substitute 2.0 kg for <em>m</em>, the mass of the pendulum, 9.81 m/s² for <em>g</em>, the acceleration due to gravity, 0.10 m for <em>h and 4.0 m/s for </em>v<em>.</em>

The pendulum has an initial energy of 20 J. the energy lost is given by,

Thus, the energy lost by the pendulum is (A) 2.0 J
Answer:
This equation is based on twin paradox - a phenomena where one of the twin travels to space at a speed close to speed of light and the other remains on earth. the twin from the space on return discovers that the one on earth age faster.
Solution:
= 10 years
v = 0.8c
c = speed of light in vacuum
The problem can be solved by time dilation equation:
(1)
where,
t = time observed from a different inertial frame
Now, using eqn (1), we get:

t = 16.67 years
The age of the twin on spaceship according to the one on earth = 25+16.67 =41.66 years
Answer:
The value of new value of angular speed of merry go round.
= 0.96 
Explanation:
Given data
r = 1.4 m
Moment of inertia
= 265 kg - 
11 RPM


= 1.15 
From conservation of momentum principal
------- (1)



Put all the values in equation (1)
265 × 1.15 = 317.92 × 
= 0.96 
This is the value of new value of angular speed of merry go round.
Answer:
the correct one is b
the difference between the final moment and the initial moment
Explanation:
The momentum is related to the moment
I = ΔP
∫ F dt = p_f - p₀
where p_f and p₀ are the final and initial moments, respectively
When checking the different answers, the correct one is b
the difference between the final moment and the initial moment
The "objective" (lens or mirror) is the major major major part of
the optical telescope. It's really the only part you need in order
to make a telescope (besides something to hold the objective).
You can put a piece of film or a CCD right at the focal point of
the objective lens or mirror and capture 'images' (pictures) there.
If you want to use the telescope for looking through and seeing stuff
with your eye, then you need the other major part ... the eyepiece lens.