Work Energy And Power Question 216

Question: The position of a particle of mass 4 g, acted upon by a constant force is given by x=4t2+t , where x is in metre and t in second. The work done during the first 2 seconds is

Options:

A) 128mJ

B) 512mJ

C) 576mJ

D) 144mJ

Show Answer

Answer:

Correct Answer: C

Solution:

[c] here, m=4,g=4×103kg

x=4t2+tdxdt=8t+1d2xdt2=8

Work done. W=fdx=md2xdt2(dtdt)dt

=02(4×103)(8)(8t+1)dt

=32×10302(8t+1)dt=32×103[8t22+t]20

=32×103[4(2)2+20]=576mJ



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