The period of any wave is the time it takes for its angle
to go from zero to 2pi .
The 'sin' function is a wave. The angle of this one is (8pi t).
When t=0, the angle is zero.
Wonderful.
Now, how long does it take for the angle to grow to 2pi ?
I*n other words, when is (8pi t) = 2pi ?
Divide each side by '2pi': . . . . . 4 t = 1
Divide each side by ' 4 ': . . . . . t = 1/4
And there you are. Every time 't' grows by 1/4, (8pi t) grows by 2pi.
So if you graph this simple harmonic motion described by 'd', you'll
see the graph wiggle up and down with a period of 1/4 .
Answer:
All are correct except the age of earth. The age of Earth is approximately 4.543 Billion Years.
Answer:
Gas is on top of oil
Explanation:
Gas is less dense ( smaller density ) than oil which is more dense. Since density is directly proportional to mass and inversely proportional to volume, gas will occupy a larger space than oil.
The larger space occupied is the space above the mixture of oil and gas, hence gas is above oil
Answer:
option B
Explanation:
given,
height of building = 0.1 km
ball strikes horizontally to ground at = 65 m
speed at which the ball strike = ?
vertical velocity = 0 m/s
time at which the ball strike
t = 4.53 s
vertical velocity at the time 4.53 s = g × t = 9.8 × 4.53 = 44.39 m/s
horizontal velocity = 
=14.35 m/s
speed of the ball = 
= 46.65 m/s
hence, the speed of the ball just before it strike the ground = 47 m/s
The correct answer is option B
