A porter lifts a heavy suitcase of mass $80\, {kg}$ and at the destination lowers it down by a distance of $80\, {cm}$ with a constant velocity. Calculate the workdone by the porter in lowering the suitcase. (take $g=9.8\, {ms}^{-2}$ ) (In ${J}$)
A porter lifts a heavy suitcase of mass $80\, {kg}$ and at the destination lowers it down by a distance of $80\, {cm}$ with a constant velocity. Calculate the workdone by the porter in lowering the suitcase. (take $g=9.8\, {ms}^{-2}$ ) (In ${J}$)
- [JEE MAIN 2021]
- A
$+627.2 {J}$
- B
$-62720.0 {J}$
- C
$784.0 {J}$
- D
$-627.2 {J}$
Similar Questions
The total work done on a particle is equal to the change in its kinetic energy. This is applicable
The total work done on a particle is equal to the change in its kinetic energy. This is applicable
A small disk can slide in a circular path on a frictionless inclined plane inclined at an angle of $30^o $ with the help of a thread as shown. Mass of the disk is $m$ and acceleration due to gravity is $g$. If the disk is released, when the thread is horizontal, expression for the tension in the thread at the lowest point is :- ................. $\mathrm{mg}$
A small disk can slide in a circular path on a frictionless inclined plane inclined at an angle of $30^o $ with the help of a thread as shown. Mass of the disk is $m$ and acceleration due to gravity is $g$. If the disk is released, when the thread is horizontal, expression for the tension in the thread at the lowest point is :- ................. $\mathrm{mg}$
A force acts on a $3 \,gm$ particle in such a way that the position of the particle as a function of time is given by $x = 3t - 4{t^2} + {t^3}$, where $x$ is in metres and $t$ is in seconds. The work done during the first $4 \,seconds$ is ..... $mJ$
A force acts on a $3 \,gm$ particle in such a way that the position of the particle as a function of time is given by $x = 3t - 4{t^2} + {t^3}$, where $x$ is in metres and $t$ is in seconds. The work done during the first $4 \,seconds$ is ..... $mJ$
- [AIPMT 1998]
A body of $0.5 \,kg$ moves along the positive $X$-axis under the influence of a varying force $F$ (in newton) as shown below.If the speed of the object at $x=4 \;m$ is $3.16 \,ms ^{-1}$, then its speed at $x=8 \,m$ is ................. $\,ms ^{-1}$
A body of $0.5 \,kg$ moves along the positive $X$-axis under the influence of a varying force $F$ (in newton) as shown below.If the speed of the object at $x=4 \;m$ is $3.16 \,ms ^{-1}$, then its speed at $x=8 \,m$ is ................. $\,ms ^{-1}$
- [KVPY 2011]
A uniform chain of mass $m$ and length $L$ is originally placed mid-way on the top of a fixed smooth double-sided wedge (Figure- $A$). The length of each side of the wedge is $L$ . It is then given a slight push. The kinetic energy of the chain when the whole chain has just slid to the left side of the wedge (Figure- $B$), is :
A uniform chain of mass $m$ and length $L$ is originally placed mid-way on the top of a fixed smooth double-sided wedge (Figure- $A$). The length of each side of the wedge is $L$ . It is then given a slight push. The kinetic energy of the chain when the whole chain has just slid to the left side of the wedge (Figure- $B$), is :