Question

43. A conservative force of (-3i)N acts on a body of
mass 3 kg. The change in potential energy of the
body due to the force, when it undergoes a
displacement 6i m is
(1) 21 J
(2) 18 J
(3) 19 J
(4) 15 J​

Answer 1

Answer:

(2) 18 J

Explanation:

1) We know, Work done by all conservative forces is given by loss in potential energy.

Represented as : $W_c=-\Delta U$

2) Now,

Here,

$Force,F=-3i\\ \\Displacement,S = 6 i m$

That is, Work done by this force is given as:

$W_c=F.s=-3i*6i=-18J$

That is, Change in Potential Energy is given by : -(-18J)=18 J

hence, option (2) is the correct answer.

Answer 2

SOLUTION.

HEY BUDDY.....

Potential energy is the energy which some what associated with confriguration of the component of the system.

You can say that negative of work done by the external agent is known as Potential energy and Mathematically it is...

du = -f.dr

where f.dr is work done by external forces

If you know the direction of the conservative field or force than the sign of change in potential energy can be defined easily....

FROM UR QUESTION...

Force = -3i

means along negative X axis

Displacement = 6i

means along positive X axis

so Change in potential energy will be positive.

du = -(-3)(6)

du = 18 joules

#answerwithquality

#BAL