Answer:
G. 2s
Explanation:
The period of a pendulum is measured in time. Out of the four options, only one of them is measured in time so it must be G.
A period of a pendulum is how long it takes to swing back to it's original position, and this time (2 seconds) is given in the question as well
Answer:
Mass of ball = 3.0102 Kg.
Explanation:
Potential energy at height h is given by
PE = mgh
where m is the mass of the body
g is the the acceleration due to gravity whose value is 9.8 m/s^2
h is the height from surface level
PE is potential energy
In the problem given h = 2 meters
PE = 59 joules
59 = m*9.8*2
=> m = 59/9.8*2 = 3.0102 Kg
Thus, mass of ball is 3.0102 Kg.
If the runner ends where she started, then her total displacement is
, which means her average velocity will be

The total distance she traversed, however, was
, which gives her an average speed of

Answer is the highest temperature, so D
Higher temperatures allow for sound to move faster, since the molecules vibrate faster, sound waves can travel more quickly. The speed of sound in room temperature air is 346 meters per second. This is faster than 331 meters per second, which is the speed of sound in air at freezing temperatures.
Neat little fact: This is also why in the winter when there is snow on the ground, it seems more peaceful and quite. The snow absorbs the sound waves and the temperature makes them not travel as fast, getting more quite as they go.
Answer:
A) Must be done 19806.62 joules of work.
B) The average power is 1320.44 Watts.
Explanation:
A) First, we're going to use the work-energy theorem that states total work (
) done on an object is equal to the change in its kinetic energy (
):
(1)
So, all we must do is to find the change on kinetic energy. Because we're working with rotational body, we should use the equation
for the kinetic energy so:
(2)
with
the initial angular velocity,
the final angular velocity (is zero because the wheel stops) and I the moment of inertia that for a thin hoop is
, using those on (2)
(3)
By (3) on (1):


B) Average power is work done divided by the time interval:


NOTE: We use the relation
to convert 280 rev/min(rpm) to 29.32 rad/s