Answer:
0.932 m/h
Explanation:
Parameters given:
Distance walked by couple, D = 1.5 km
Time spent in walking, t = 60 min
To solve this we simply apply the formula for average peed:
Average Speed = total distance / total time taken
The question asks specifically to put the answer in miles per hour (m/h), hence, we need to convert the distance to miles and the time to hours:
Distance in miles:
1 km = 0.622 miles
1.5 km = 1.5 * 0.622 = 0.932 miles
Time in hours = 60 / 60 = 1 hour
Hence, the speed is:
Speed = 0.932 / 1 = 0.932 m/h
The average speed of the couple is 0.932 m/h
Presently, the speed of light in a vacuum is defined to be exactly 299,792,458 m/s (approximately 186,282 miles per second). . An early experiment to measure the speed of light was conducted by Ole Romer, a Danish physicist, in 1676. Using a telescope, Ole observed the motions of Jupiter and one of its moons, Io
(a) 
The gravitational potential energy of the two-sphere system is given by
(1)
where
G is the gravitational constant
is the mass of sphere A
is the mass of sphere B
r = 1.8 m is the distance between the two spheres
Substitutign data in the formula, we find
and the sign is negative since gravity is an attractive force.
(b) 
According to the law of conservation of energy, the kinetic energy gained by sphere B will be equal to the change in gravitational potential energy of the system:
(2)
where
is the initial potential energy
The final potential energy can be found by substituting
r = 1.80 m -0.60 m=1.20 m
inside the equation (1):
U=-\frac{(6.67\cdot 10^{-11})(94 kg)(100 kg)}{1.2 m}=-5.22\cdot 10^{-7} J
So now we can use eq.(2) to find the kinetic energy of sphere B:
Answer:
The speed of the laser light in the cable, 
Explanation:
It is given that,
Wavelength of Argon laser, 
Refractive index, n = 1.46
Let 
is the speed of the laser light in the cable. The speed of light in a medium is given by :
or
So, the speed of the laser light is 
. Hence, this is the required solution.
