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.

Answer:

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.

**Answer:**

A any air resistance

**Explanation:**

a body in freefall donot experience

Answer:

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

Eb= 0.00227mm/mm

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)

= 39.79MPa

Es= 39.79/ 45×10^9 =0.000884mm/mm