The guy below is wrong!
F=ma
Where force = mass x acceleration
We dont have acceleration, a= change in velocity divided by the time taken.
a = v (final velocity) - u (initial) / t
a us 8-0 (at rest means u was 0) / 20 = 0.4
Using F=ma
F= mass x acceleration
F= 4 x 0.4
F=1.6 N
Answer:
85.5 km/h
Explanation:
= time interval for first phase = 14 min = 
h = 0.233 h
= time interval for second phase = 46 min = 
h = 0.767 h
= average speed for the entire trip = 74 km/h
= average speed in first phase = 36 km/h
= average speed in second phase
= distance traveled in first phase
= distance traveled in first phase
average speed is given as
km/h
B. Sound, because everything else sits still and sound waves move
Answer:
I should be active for 15 hours to meet the physical activity requirement.
Explanation:
Since time dilates in moving objects, we use the formula t = t₀/√(1 - β²) where t = time in space vehicle, t₀ = time on earth = 9 hours and β = v/c where v = speed of space vehicle = 0.8c.
So, t = t₀/√(1 - β²)
t = 9/√(1 - (v/c)²)
= 9/√(1 - (0.8c/c)²)
= 9/√(1 - (0.8)²)
= 9/√(1 - (0.64)
= 9/√0.36
= 9/0.6
= 15 hr
So, according to a timer on the space vehicle, I should be active for 15 hours to meet the physical activity requirement.
Given :
Number of operations move through a pocket calculator during a full day's operation , 
.
To Find :
How many coulombs of charge moved through it .
Solution :
We know , charge in one electron is :
So , charge on n electron is :
Therefore , -21.44 coulombs of charge is moved through it .
Hence , this is the required solution .
