Physics/Math

posted by .

A single force acts on a 5.0 kg particle-like object in such a way that the position of the object as a function of time is given by x = 3.0t - 4.0t 2 + 1.0t 3, with x in meters and t in seconds. Find the work done on the object by the force from t = 0 to t = 2.0 s.

For Further Reading

* Physics/Math - bobpursley, Thursday, March 1, 2007 at 6:28am

find the position at at t=2 and t=0. The difference in those is the displacement.

Work= force times displacement.

* Physics/Math - Technoboi11, Friday, March 2, 2007 at 12:11am

So when t=0, x=0.
When t=2, x=-2
displacement= -2-0 = -2m

W=Fd
F=ma=(5)(9.8)=49

W=(49 N)(-2 m)
W= -98 J

This is the answer that I got but it is an incorrect answer. Is there something wrong with my calculations???

x= 3.0t - 4.0t^ 2 + 1.0t^3
dx/dt= 3 - 8 t + 3t^2

d"x/dt"= acceleration= -8 + 6 t

F= ma = m (-8+6t)
INT F dx= work
work = INT m (-8+6t)(3 - 8 t + 3t^2)dt

integrate from t=0 to t= 2.

check my thinking.



Can you use W=1/2mv1^2-1/2mv2^2
Use 3-8t+3t^2 and solve for v1 when t=0 and v2 when t=2. Then plug v1 and v2 into the above equation with 5 as mass?

I used the above equation and it worked

  • Physics/Math -

    Use your last equation. Do not use d"x/dt" because this force is a variable force, and F = ma is not applicable here, I think.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. Physics/Math

    A single force acts on a 5.0 kg particle-like object in such a way that the position of the object as a function of time is given by x = 3.0t - 4.0t 2 + 1.0t 3, with x in meters and t in seconds. Find the work done on the object by …
  2. Re: Physics/Math

    A single force acts on a 5.0 kg particle-like object in such a way that the position of the object as a function of time is given by x = 3.0t - 4.0t 2 + 1.0t 3, with x in meters and t in seconds. Find the work done on the object by …
  3. Physics/Math

    At a certain instant, a particle-like object is acted on by a force F = (3.0 N) i - (1.0 N) j + (8.0 N) k while the object's velocity is v = - (2.0 m/s) i + (4.0 m/s) k. What is the instantaneous rate at which the force does work on …
  4. physics

    If only a single nonzero force acts on an object, does the object accelerate relative to all inertial reference frames?
  5. physics

    (a)At a certain instant, a particle-like object is acted on by a force F = (4.0 N)i - (2.0 N)j + (9.0 N)k while the object's velocity is v = - (2.0 m/s)i + (4.0 m/s)k . What is the instantaneous rate at which the force does work on …
  6. Physics

    At a certain instant, a particle-like object is acted on by a force F = (4.0 N) - (2.0 N) + (9.0 N) while the object's velocity is v = - (2.0 m/s) + (4.0 m/s) . What is the instantaneous rate at which the force does work on the object?
  7. Physics

    (a) At a certain instant, a particle-like object is acted on by a force F = (3.0 N) - (1.0 N) + (8.0 N) while the object's velocity is v = - (2.0 m/s) + (4.0 m/s) . What is the instantaneous rate at which the force does work on the …
  8. Physics

    Please Help. A 5 kg object is propelled from rest at time t=0 by a net force F that always acts in the same direction. The magnitude of F in newtons is given as a function of t in seconds by F= 0.5t. What is the speed of the object …
  9. Physics

    In a 1-dimensional problem, a single force acts on a 10 kg object and is given the equation F=ax+b where a=250 N/m, b=25 N, x is position of object. There is a force acting on the object while that object moves from x=0 to x=2 lasting …
  10. Physics

    A single force acts on a 1.1 kg particle-like object in such a way that the position of the object as a function of time is given by x = 4.1t - 3.6t2 + 4.5t3, with x in meters and t in seconds. Find the work done on the object by the …

More Similar Questions