NEET Test Series from KOTA - 10 Papers In MS WORD
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Work, Energy and Power
268701
A uniform cylinder of radius ' \(r\) ' length ' \(L\) ' and mass ' \(m\) ' is lying on the ground with the curved surface touching the ground. If it is to be oriented on the ground with the flat circular end in contact with the ground, the work to be done is
1 mg[(L/2)-r]
2 mL[(g/2)-r]
3 mr(gL-1)
4 mgLr
Explanation:
\(W=U_{i}-U_{f}\); where \(U_{i}=m g h_{1} ; U_{f}=m g h_{2}\);
\(\therefore \mathrm{W}=\mathrm{mg}\left(h_{1}-h_{2}\right)\)
Work, Energy and Power
268702
A meter scale of mass \(400 \mathrm{gm}\) is lying horizontally on the floor. If it is to be held vertically with one end touching the floor, the work to be done is
1 \(6 \mathrm{~J}\)
2 \(4 \mathrm{~J}\)
3 \(40 \mathrm{~J}\)
4 \(2 \mathrm{~J}\)
Explanation:
\(\quad W=\vec{F} \cdot \vec{S}=F S_{c o m}\); where \(\mathrm{F}=\mathrm{mg}\) and \(S_{c o m}=\frac{L}{2}\)
Work, Energy and Power
268703
A force \(\mathrm{F}\) is applied on a lawn mover at an angle of \(60^{\circ}\) with the horizontal. If it moves through a distance \(x\), the work done by the force is
268704
A weight lifter jerks \(220 \mathrm{~kg}\) vertically through 1.5 metre and holds still at that height for two minutes. The work done by him in lifting and in holding it still are respectively
1 \(220 \mathrm{~J}, 330 \mathrm{~J}\)
2 \(3234 \mathrm{~J}, 0 \mathrm{~J}\)
3 \(2334 \mathrm{~J}, 10 \mathrm{~J}\)
4 \(0 \mathrm{~J}, 3234 \mathrm{~J}\)
Explanation:
\(\mathrm{W}=\vec{F} \cdot \vec{S}=F S \cos \theta\)
In lifting the weight \(F=m g, \theta=0^{0}\);
in holding the weight, \(S=0\)
268701
A uniform cylinder of radius ' \(r\) ' length ' \(L\) ' and mass ' \(m\) ' is lying on the ground with the curved surface touching the ground. If it is to be oriented on the ground with the flat circular end in contact with the ground, the work to be done is
1 mg[(L/2)-r]
2 mL[(g/2)-r]
3 mr(gL-1)
4 mgLr
Explanation:
\(W=U_{i}-U_{f}\); where \(U_{i}=m g h_{1} ; U_{f}=m g h_{2}\);
\(\therefore \mathrm{W}=\mathrm{mg}\left(h_{1}-h_{2}\right)\)
Work, Energy and Power
268702
A meter scale of mass \(400 \mathrm{gm}\) is lying horizontally on the floor. If it is to be held vertically with one end touching the floor, the work to be done is
1 \(6 \mathrm{~J}\)
2 \(4 \mathrm{~J}\)
3 \(40 \mathrm{~J}\)
4 \(2 \mathrm{~J}\)
Explanation:
\(\quad W=\vec{F} \cdot \vec{S}=F S_{c o m}\); where \(\mathrm{F}=\mathrm{mg}\) and \(S_{c o m}=\frac{L}{2}\)
Work, Energy and Power
268703
A force \(\mathrm{F}\) is applied on a lawn mover at an angle of \(60^{\circ}\) with the horizontal. If it moves through a distance \(x\), the work done by the force is
268704
A weight lifter jerks \(220 \mathrm{~kg}\) vertically through 1.5 metre and holds still at that height for two minutes. The work done by him in lifting and in holding it still are respectively
1 \(220 \mathrm{~J}, 330 \mathrm{~J}\)
2 \(3234 \mathrm{~J}, 0 \mathrm{~J}\)
3 \(2334 \mathrm{~J}, 10 \mathrm{~J}\)
4 \(0 \mathrm{~J}, 3234 \mathrm{~J}\)
Explanation:
\(\mathrm{W}=\vec{F} \cdot \vec{S}=F S \cos \theta\)
In lifting the weight \(F=m g, \theta=0^{0}\);
in holding the weight, \(S=0\)
268701
A uniform cylinder of radius ' \(r\) ' length ' \(L\) ' and mass ' \(m\) ' is lying on the ground with the curved surface touching the ground. If it is to be oriented on the ground with the flat circular end in contact with the ground, the work to be done is
1 mg[(L/2)-r]
2 mL[(g/2)-r]
3 mr(gL-1)
4 mgLr
Explanation:
\(W=U_{i}-U_{f}\); where \(U_{i}=m g h_{1} ; U_{f}=m g h_{2}\);
\(\therefore \mathrm{W}=\mathrm{mg}\left(h_{1}-h_{2}\right)\)
Work, Energy and Power
268702
A meter scale of mass \(400 \mathrm{gm}\) is lying horizontally on the floor. If it is to be held vertically with one end touching the floor, the work to be done is
1 \(6 \mathrm{~J}\)
2 \(4 \mathrm{~J}\)
3 \(40 \mathrm{~J}\)
4 \(2 \mathrm{~J}\)
Explanation:
\(\quad W=\vec{F} \cdot \vec{S}=F S_{c o m}\); where \(\mathrm{F}=\mathrm{mg}\) and \(S_{c o m}=\frac{L}{2}\)
Work, Energy and Power
268703
A force \(\mathrm{F}\) is applied on a lawn mover at an angle of \(60^{\circ}\) with the horizontal. If it moves through a distance \(x\), the work done by the force is
268704
A weight lifter jerks \(220 \mathrm{~kg}\) vertically through 1.5 metre and holds still at that height for two minutes. The work done by him in lifting and in holding it still are respectively
1 \(220 \mathrm{~J}, 330 \mathrm{~J}\)
2 \(3234 \mathrm{~J}, 0 \mathrm{~J}\)
3 \(2334 \mathrm{~J}, 10 \mathrm{~J}\)
4 \(0 \mathrm{~J}, 3234 \mathrm{~J}\)
Explanation:
\(\mathrm{W}=\vec{F} \cdot \vec{S}=F S \cos \theta\)
In lifting the weight \(F=m g, \theta=0^{0}\);
in holding the weight, \(S=0\)
268701
A uniform cylinder of radius ' \(r\) ' length ' \(L\) ' and mass ' \(m\) ' is lying on the ground with the curved surface touching the ground. If it is to be oriented on the ground with the flat circular end in contact with the ground, the work to be done is
1 mg[(L/2)-r]
2 mL[(g/2)-r]
3 mr(gL-1)
4 mgLr
Explanation:
\(W=U_{i}-U_{f}\); where \(U_{i}=m g h_{1} ; U_{f}=m g h_{2}\);
\(\therefore \mathrm{W}=\mathrm{mg}\left(h_{1}-h_{2}\right)\)
Work, Energy and Power
268702
A meter scale of mass \(400 \mathrm{gm}\) is lying horizontally on the floor. If it is to be held vertically with one end touching the floor, the work to be done is
1 \(6 \mathrm{~J}\)
2 \(4 \mathrm{~J}\)
3 \(40 \mathrm{~J}\)
4 \(2 \mathrm{~J}\)
Explanation:
\(\quad W=\vec{F} \cdot \vec{S}=F S_{c o m}\); where \(\mathrm{F}=\mathrm{mg}\) and \(S_{c o m}=\frac{L}{2}\)
Work, Energy and Power
268703
A force \(\mathrm{F}\) is applied on a lawn mover at an angle of \(60^{\circ}\) with the horizontal. If it moves through a distance \(x\), the work done by the force is
268704
A weight lifter jerks \(220 \mathrm{~kg}\) vertically through 1.5 metre and holds still at that height for two minutes. The work done by him in lifting and in holding it still are respectively
1 \(220 \mathrm{~J}, 330 \mathrm{~J}\)
2 \(3234 \mathrm{~J}, 0 \mathrm{~J}\)
3 \(2334 \mathrm{~J}, 10 \mathrm{~J}\)
4 \(0 \mathrm{~J}, 3234 \mathrm{~J}\)
Explanation:
\(\mathrm{W}=\vec{F} \cdot \vec{S}=F S \cos \theta\)
In lifting the weight \(F=m g, \theta=0^{0}\);
in holding the weight, \(S=0\)
