Question

If body constrained to move in z direction is subjected to a force given by f=3i^-10j^+5k^. What is the work done by this force in moving the body through a distance of 5m along z axis

Answer 1

As the body can move only in z direction then only the component of force in z direction will do work.
W = 5 × 5 = 25 J

Answer 2

➡GIVEN:-
force = f = 3i-10j+5k
distance=5m along axis=5k
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▶FORMULA USED:-

work done =(force)(displacement)(cosθ)

=> work done= (force).(displacement)
i.e. work is the dot product or scalar product of force and displacement
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➡ANSWER:-

=> work = ( 3i-10j+5k)(5k)

=> work= 3(0)(i.i)+(-10)(0)(j.j)+(5)(5)(k.k)

{as we know...
i.i=j.i=k.k=1}

=> work=3(0)+(-10)(0)+5(5)

=> work done= 25joules
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hope it helps you
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