Answer:
h = 181.73 m
Explanation:
given,
distance between the neighbors = 42 m
speed of the rock rolling = 6.9 m/s
vertical velocity of ball = 0 m/s
height of the cliff = ?
time taken by the ball to travel 42 m
d = s x t
s is the horizontal speed of the ball equal to 6.9 m/s


t = 6.09 s
same time will be taken by the ball to travel vertical distance
Using equation of motion



h = 181.73 m
Answer:
<em>I must travel with a speed of 2.97 x 10^8 m/s</em>
Explanation:
Sine the spacecraft flies at the same speed in the to and fro distance of the journey, then the time taken will be 6 months plus 6 months
Time that elapses on the spacecraft = 1 year
On earth the people have advanced 120 yrs
According to relativity, the time contraction on the spacecraft is gotten from
= 
where
is the time that elapses on the spacecraft = 120 years
= time here on Earth = 1 year
is the ratio v/c
where
v is the speed of the spacecraft = ?
c is the speed of light = 3 x 10^8 m/s
substituting values, we have
120 = 1/
squaring both sides of the equation, we have
14400 = 1/
14400 - 14400
= 1
14400 - 1 = 14400
14399 = 14400
= 14399/14400 = 0.99
= 0.99
substitute β = v/c
v/c = 0.99
but c = 3 x 10^8 m/s
v = 0.99c = 0.99 x 3 x 10^8 = <em>2.97 x 10^8 m/s</em>
Answer:
The ratio of the orbital time periods of A and B is 
Solution:
As per the question:
The orbit of the two satellites is circular
Also,
Orbital speed of A is 2 times the orbital speed of B
(1)
Now, we know that the orbital speed of a satellite for circular orbits is given by:

where
R = Radius of the orbit
Now,
For satellite A:

Using eqn (1):
(2)
For satellite B:
(3)
Now, comparing eqn (2) and eqn (3):

Answer:
2.55sec
Explanation:
time = distance/speed = (87 m)/(34 m/s) = 2.55sec
To solve this problem we need to apply the corresponding sound intensity measured from the logarithmic scale. Since in the range of intensities that the human ear can detect without pain there are large differences in the number of figures used on a linear scale, it is usual to use a logarithmic scale. The unit most used in the logarithmic scale is the decibel yes described as

Where,
I = Acoustic intensity in linear scale
= Hearing threshold
The value in decibels is 17dB, then

Using properties of logarithms we have,




Therefore the factor that the intensity of the sound was 