Answer:
Mary's average speed is 0.42 meters/second.
Explanation:
Mary's total travel was 250 meters and the elapsed time was 10 minutes, equivalent to 600 seconds.
d = displacement = 80 meters + 125 meters + 45 meters = 250 meters
t = time = 10 minutes . 60 seconds/minute = 600 seconds
We can obtain now the average speed:
s = average speed = displacement / time = 250 meters / 600 seconds ≅ 0.4167 ≅ 0.42
Answer:
<em>Speed of the electron is 2.46 x 10^8 m/s</em>
<em></em>
Explanation:
momentum of the electron before relativistic effect = 
where
is the rest mass of the electron
V is the velocity of the electron.
under relativistic effect, the mass increases.
under relativistic effect, the new mass M will be
M = 
where

c is the speed of light = 3 x 10^8 m/s
V is the speed with which the electron travels.
The new momentum will therefore be
==> 
It is stated that the relativistic momentum is 1.75 times the non-relativistic momentum. Equating, we have
1.75
= 
the equation reduces to
1.75 = 
square both sides of the equation, we have
3.0625 = 1/
3.0625 - 3.0625
= 1
2.0625 = 3.0625
= 0.67
β = 0.819
substitute for 
V/c = 0.819
V = c x 0.819
V = 3 x 10^8 x 0.819 = <em>2.46 x 10^8 m/s</em>
D.
50 mph - 30 mph= 20 mph net velocity
change.
20mph/3600 seconds/hour= .00555 MPS
.0055 miles per second
40 seconds to complete the change
.0055/40= .000138