Motion must be defined relative to something.
Here's an obvious, everyday example:
-- You're in a passenger jet, going to visit grandma on the
coast for the holidays.
-- You're sitting still in your seat, listening to some 'mp3's,
reading a book, and dozing off.
-- At the same time, people on the ground see you flying over
at almost 500 miles per hour.
Are you moving at 500 mph, or are you not moving at all ?
The answer is 'Yes. Both.'. It just depends on who's measuring your speed.
There's no such thing as your "real" speed. Motion is always
relative to something. Different reference = different speed.
We know that velocity equals to difference in distance divided by difference in time.
1st period: velocity is increasing. Where v = (8-0)/(3-0) = 8/3 m/s.
2nd one: velocity decreases. Where
v=(5-8)/(4-3) = (-3) m/s.
3rd one: velocity is constant because no change in distance, so v=0.
4th one: velocity increases again. Where v=(10-5)/(8-6)= 5/2 m/s.
5th one: velocity is constant again, so v=0.
6th one: velocity decreases, where
v=(6-10)/(15-12)= (-4)/3 m/s.
For this we need to use several formulas:
v = a*t
This simply means that after 1 second we will have some speed and if we double time, speed will double as well.
But, relation time-traveled distance isn't linear. Traveled distance we calculate:
s = 1/2*a*t^2 we can say that h=s
so if we double time, traveled distance will increase 4 times because of square relation between time and traveled distance.
New traveled distance (h2) will be: h2=4*h
b) Because distance depends on gravity acceleration in free fall h2 will certainly change but the relation h2=4*h will remain the same.
A any air resistance
a body in freefall donot experience
Strain on bolt= 159.15MPa
Strain on sleeve = 39.79MPa
Stress on bolt= 0.00227mm/km
Stress on sleeve= 0.000884mm/mm
Explanation: Given : do= 20mm , di= 12mm , p= 8 × 10^3N, Eol= 70Gpa , Emg = 45Gpa
Normal stress = P/Ab
Ab= pi/4 ×d^2=3.142/4 × (8 × 10^-3)^2
Ab = 5.024× 10^-5m^2
Stress of bolt= 8×10^3/5.024×10^5=159.15Mpa
Eb= stress on bolt= 159.15×10^6/70×10^9
For the sleeve
Normal stress= P/As As= pi×d^2/4 =3.142/4× ((20×10^-3)-(12×10^-3))^2
As = 5.024× 10^-5m
Stress on sleeve = 8×10^3/5.024×10^-5)
Es= 39.79/ 45×10^9 =0.000884mm/mm