A tourist leaves Pittsburgh and travels 60 miles South on I-79 in 45 minutes. They exit after Wheeling and head west on I-70 and
1 answer:
Answer:
<em>The tourist's average speed was 80 mph</em>
Explanation:
<u>Average Speed </u>
If an object travels a distance d in a time t regardless of the direction, the average speed is the quotient of the distance over the time:
The tourist leaves Pittsburgh and travels 60 miles South in 45 minutes. Then he heads West and travels 100 miles in 1 hour and 15 minutes.
The total distance traveled is:
d = 60 miles + 100 miles = 160 miles
The total time is:
t = 45 minutes + 1 hour + 15 minutes = 2 hours
The average speed is:
v = 80 mph
The tourist's average speed was 80 mph
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Answer:
The work function ϕ of the metal = 53.4196 x 10⁻¹⁶ J
Explanation:
When light is incident on a photoelectric material like metal, photoelectrons are emitted from the surface of the metal. This process is called photoelectric effect.
The relationship between the maximum kinetic energy () of the photoelectrons to the frequency of the absorbed photons (f) and the threshold frequency (f₀) of the photoemissive metal surface is:
= h(f − f₀)
= hf - hf₀
E is the energy of the absorbed photons: E = hf
ϕ is the work function of the surface: ϕ = hf₀
= E - ϕ
Frequency f = 8.12×10¹⁸ Hz
Maximum kinetic energy = 4.16×10⁻¹⁷ J
Speed of light c = 3 x 10⁸ m/s
Planck's constant h = 6.63 × 10⁻³⁴ Js
E = hf = 6.63 × 10⁻³⁴ x 8.12×10¹⁸
E = 53.8356 x 10⁻¹⁶ J
from = E - ϕ ;
ϕ = E -
ϕ = 53.8356 x 10⁻¹⁶ - 4.16×10⁻¹⁷
ϕ = 53.4196 x 10⁻¹⁶ J
The work function of the metal ϕ = 53.4196 x 10⁻¹⁶ J
Answer:
The density of plastic is equal to 0.6 g/mL.
Explanation:
Given that,
The mass of piece of plastic, m = 15 g
It is placed in a graduated cylinder. The water level in the graduated cylinder rises from 30 mL to 55 mL when the plastic is added.
We need to find the density of plastic.
Rise in volume = 55 mL - 30 mL
= 25 mL
The density of an object is given by :
So, the density of plastic is equal to 0.6 g/mL.