JEE Main · 2019 · 08 Apr 2019 · Shift 1 · Work, Power & Energy

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A particle moves in one dimension from rest under the influence of a force that varies with the distance traveled by the particle as shown in the figure. The kinetic energy of the particle after it has traveled 3 m is:

(A)2.5 J
(B)4 J
(C)5 J
(D)6.5 J✓ Correct

Answer: (D)

Solution

By the work-energy theorem the kinetic energy gained from rest equals the work done, which is simply the area under the force-distance graph out to

3

m. Reading the graph, the first

2

m give a rectangle of area

2 \times 2 = 4

J and the final metre gives a trapezium of area

\frac{( 2 + 3 ) \times 1}{2} = 2.5

J. The total work, and hence the kinetic energy after

3

m, is

4 + 2.5 = 6.5

JEE Main · 2019 · 08 Apr 2019 · Shift 1 · Single correct option

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