Explore popular questions from Work, Energy and Power for JEE Advanced. This collection covers Work, Energy and Power previous year JEE Advanced questions hand picked by experienced teachers.

## Chemistry

Work, Energy and Power

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Q 1. Two masses of 1 {tex} \mathrm { gm } {/tex} and 4 {tex} \mathrm { gm } {/tex} are moving with equal kinetic energies. The ratio of the magnitudes of their linear momenta is

A

{tex}4:1{/tex}

B

{tex} \sqrt { 2 }: 1 {/tex}

{tex}1:2{/tex}

D

{tex}1:16{/tex}

##### Explanation

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Q 2. A spring of force-constant {tex} k {/tex} is cut into two pieces such that one piece is double the length of the other. Then the long piece will have a force-constant of

A

{tex} ( 2 / 3 ) k {/tex}

{tex} ( 3 / 2 ) k {/tex}

C

{tex} 3 k {/tex}

D

{tex} 6 k {/tex}

##### Explanation

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Q 3. If {tex} W _ { 1 } , W _ { 2 } {/tex} and {tex} W _ { 3 } {/tex} represent the work done in moving a particle from {tex} A {/tex} to {tex} B {/tex} along three different paths {tex} 1,2 {/tex} and {tex}3{/tex} respectively (as shown) in the gravitational field of a point mass {tex} m , {/tex} find the correct relation between {tex} W _ { 1 } , W _ { 2 } {/tex} and {tex} W _ { 3 } {/tex}

A

{tex} W _ { 1 } > W _ { 2 } > W _ { 3 } {/tex}

{tex} W _ { 1 } = W _ { 2 } = W _ { 3 } {/tex}

C

{tex} W _ { 1 } < W _ { 2 } < W _ { 3 } {/tex}

D

{tex} W _ { 2 } > W _ { 1 } > W _ { 3 } {/tex}

##### Explanation

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Q 4. A block {tex} ( B ) {/tex} is attached to two unstretched springs {tex} S _ { 1 } {/tex} and {tex} S _ { 2 } {/tex} with spring constants {tex} k {/tex} and {tex} 4 k , {/tex} respectively (see fig. I). The other ends are attached to identical supports {tex} M _ { 1 } {/tex} and {tex} M _ { 2 } {/tex} not attached to the walls. The springs and supports have negligible mass. There is no friction anywhere. The (figure II) and released. The block returns and moves a maximum distance {tex} y {/tex} towards wall {tex} 2 . {/tex} Displacements {tex} x {/tex} and {tex} y {/tex} are measured with respect to the equilibrium position of the block {tex} B {/tex}. The ratio {tex} y / x {/tex} is -

A

{tex} 4 {/tex}

B

{tex} 2 {/tex}

{tex} 1 / 2 {/tex}

D

{tex} 1 / 4 {/tex}

##### Explanation

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Q 5. A block of mass {tex} 2 \mathrm { kg } {/tex} is free to move along the x-axis. It is at rest and from {tex} \mathrm { t } = 0 {/tex} onwards it is subjected to a time-dependent force {tex} F ( t ) {/tex} in the {tex} x {/tex} direction. The force {tex} F ( t ) {/tex} varies with {tex} t {/tex} as shown in the figure. The kinetic energy of the block after {tex}4.5{/tex} seconds is

A

{tex} 4.50 \mathrm { J } {/tex}

B

{tex} 7.50 \mathrm { J } {/tex}

{tex} 5.06 \mathrm J {/tex}

D

{tex} 14.06 \mathrm { J } {/tex}

##### Explanation

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Q 6. A tennis ball is dropped on a horizontal smooth surface. It bounces back to its original position after hitting the surface. The force on the ball during the collision is proportional to the length of compression of the ball. Which one of the following sketches describes the variation of its kinetic energy {tex} K {/tex} with time {tex} t {/tex} most appropriately? The figure are only illustrative and not to the scale.

A

C

D