Pushing force making an angle theta to the horizontal is applied on a block of weight w placed ona a horizontal table. If the angle of friction is alpha, the magnitude of force required to move the body is equal to

a) (w cos(alpha))/(cos(theta+alpha))

b) (w sin(theta))/(cos(theta+alpha))

c) (w tan(theta))/(sin(theta+alpha))

d) (w sin(alpha))/(tan(theta+alpha))

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N=normalF=force requiredf=frictionN=w+Fsin(theta)tan(alpha)=muf=tan(alpha)[w+fsin(theta)]Fcos(theta)=tan(alpha)[w+Fsin(theta)]F[cos(theta)-tan(theta)sin(theta)]= tan(alpha)wF=[wsin(alpha)]/[cos(theta)*cos(alpha)- sin(theta)*sin(alpha)]F=wsin(alpha)/cos(alpha+theta)