Question About Assignment - accelerations, velocities and distances

[shinnsohai]

Question About Assignment -- accelerations, velocities and distances

Homework Statement

Q1.

Homework Equations

Q1.What will be the distance traveled by each buses since t=0s?

Q2. Explain how it is possible for
1.a body to undergo acceleration even though it is momentarily at rest
2.a body to undergo acceleration when it is moving with constant speed
3.a body to undergo deceleration when its speed increase

Q3: why is paraffin wax, which has a high concentration of protons, a good absorber of high speed neutrons?

The Attempt at a Solution

Q1:From my understanding, when t=0 there is no movement so distance = 0
by extending the graph, which the line will be touched the x-axis(x intercept) it's not possible to have negative time.

Q2:Sorry for bad English Understanding(From my understanding, the sentence how it is possible for means that these cases are true but with certain condition then it will occur.

1:external force - gravitational forces OR the surrounding environment is moving(eg Aeroplane?)
2:external force - gravitational forces
3:Frictional force

Q3:Never encounter these before, maybe paraffin wax have high concentration of protons whenever the radiation hit it it could produce high speed neutrons ?? kind ar blurr
(Source : http://www-outreach.phy.cam.ac.uk/camphy/neutron/neutron3_1.htm )

 

[Infinitum]

Question 1 is unclear. It asks you for the distance traveled by the buses since t=0, but without specifying the interval, so it doesn't make sense. Looking at the graph, they are probably asking you for t=20sec or at a general time 't', so you should be able to calculate it using basic equations of motion.

Question 2, you have got part (a) correct. But for part (b), in which case of gravitational forces is the velocity constant?? Hint : Think about motion where speed remains constant but direction of velocity changes.

 

[daniel.e2718]

DELETED: I posted work to everything. I apologize for not following the guidelines!

 

[azizlwl]

3. Yes its negative acceleration if the body is speeding in negative direction or maybe just say it is reversing.

 

[shinnsohai]

thanks for replying guys~
imma appreciate it very much