Answer:
300 miles per hour
Explanation:
Speed is distance per unit time, expressed as s=d/t where t is the time taken, d is distance covered and s is the speed.
Convering s to hrs
To convert seconds to hours, we knkw that 1 hour has 60 minutes and each minute has 60 seconds. Therefore, 1 hour has 60*60=3600 seconds
If 3600s=1 h
60 s=?
By cross multiplication 60s*1 h/3600s=1/60 hours
Given distance as 5 miles and time as 1/60 hours then the speed will be 5 divided by 1/60 hrs which is equivalent to 5*60=300 miles per hour
When light moves from a medium with higher refractive index to a medium with lower refractive index, the critical angle is the angle above which there is no refracted ray, and it is given by:
(2)
where
is the refractive index of the second medium and
is the refractive index of the first medium.
We can find the ratio
by using Snell's law:
(1)
where
is the angle of incidence
is the angle of refraction
By using the data of the problem and re-arranging (1), we find
and if we use eq.(2) we can now find the value of the critical angle:
Simialar results with the claim
Answer:
Positive sign for negative velocity and minus sing for positive velocity
Explanation:
In the case of the negative velocity, the sign of the acceleration that reduces its magnitude is the positive sign, since being in the opposite direction to the movement indicates a deceleration or braking. In the case of the positive velocity, the sign of the acceleration that reduces its magnitude is the negative sign, since being in the opposite direction to the movement indicates a deceleration or braking. We observe that there will always be a reduction in the magnitude of the velocity if the acceleration goes in the opposite direction.