Question 117: Work, Energy and Power & Circular Motion

Question

Given below is the plot of a potential energy function U(x) for a system, in which a particle is in one dimensional motion, while a conservative force F(x) acts on it. Suppose that E
mech
= 8 J, the incorrect statement for this system is :
[ where K.E. = kinetic energy ]

Accepted Answer

E
mech.
= 8J
(A) at x > x
4
U = constant = 6J
K = E
mech.
$$-$$ U = 2J = constant
(B) at x < x
1
U = constant = 8J
K = E
mech
$$-$$ U = 8 $$-$$ 8 - 0 J
Particle is at rest.
(C) At x = x
2
,
U = 0 $$\Rightarrow$$ E
mech.
= K = 8 J
KE is greatest, and particle is moving at fastest speed.
(D) At x = x
3
U = 4J
U + K = 8J
K = 4J

Answer

at x > x
4
K.E. is constant throughout the region.

Answer

at x < x
1
, K.E. is smallest and the particle is moving at the slowest speed.

Answer

at x = x
2
, K.E. is greatest and the particle is moving at the fastest speed.

Answer

at x = x
3
, K.E. = 4 J.

Work, Energy and Power & Circular Motion

Given below is the plot of a potential energy function U(x) for a system, in which a particle is in one dimensional motion, while a conservative force F(x) acts on it. Suppose that E mech = 8 J, the incorrect statement for this system is : [ where K.E. = kinetic energy ]

Choose the correct answer: