What is the velocity and time needed to solve this kinematics problem?

AI Thread Summary
The discussion revolves around solving a kinematics problem involving a particle with acceleration defined as a = -k√v. The user seeks assistance in determining the particle's velocity at x = 24 m and the time required for it to come to rest, given initial conditions of x = 0, v = 81 m/s at t = 0, and v = 36 m/s at x = 18 m. The user attempted to use the equations a = v(dv/dx) and a = dv/dt for integration but encountered difficulties. Other participants are encouraged to share their calculations and insights to help resolve the issue. The user expresses willingness to return for further assistance if needed.
lidakeo
Messages
3
Reaction score
0
Hi guys. I'm new here. If i did any mistake please forgive me.



First of all I have a simple problem need all of you to help me.



Here is the problem


The acceleration of a particle is defined by the relation a = -k√v, where k is constant.
Knowing that
x = 0 and v = 81 m/s at t = 0
and v = 36 m/s x = 18 m

determine
(a) the velocity of the particle when x = 24 m
(b) the time required for the particle to come to rest.
 
Physics news on Phys.org
using ##a=v\frac{dv}{dx}## or ##a=\frac{dv}{dt}## and some integration, can you find a relation between v and x?
 
MrWarlock616 said:
using ##a=v\frac{dv}{dx}## or ##a=\frac{dv}{dt}## and some integration, can you find a relation between v and x?


I did but it not work for me. Maybe I missed some part. I'll try again. Thank for reply.
 
You can post your calculations if you are stuck. :smile:
 
MrWarlock616 said:
You can post your calculations if you are stuck. :smile:

I'll reply back. If I got stuck again. :smile:
 
Thread 'Variable mass system : water sprayed into a moving container'
Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
Back
Top