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JEE Main

IMPORTANT

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It is found that if a neutron suffers an elastic collinear collision with a deuterium at rest, the fractional loss of its energy is $P_{d}$ , while for its similar collision with a carbon nucleus at rest, the fractional loss of energy is $P_{c}$ . The values of $P_{d}$ and $P_{c}$ are respectively

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Important Questions on Work, Energy and Power

MEDIUM

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Work, Energy and Power>JEE Main - 16th April 2018>Q 75

A body of mass

m

starts moving from rest along

x -

axis so that its velocity varies as

v = a \sqrt{s}

where

a

is a constant and

s

is the distance covered by the body. The total work done by all the forces acting on the body in the first

t

second after the start of the motion is

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Work, Energy and Power>JEE Main - 16th April 2018>Q 76

An oscillator of mass

M

is at rest in its equilibrium position in a potential,

V = \frac{1}{2} k {(x - X)}^{2}

. A particle of mass

m

comes from the right with speed

u

and collides completely inelastic with

M

and sticks to it. This process repeats every time the oscillator crosses its equilibrium position. The amplitude of oscillations after

13

collisions is:

(M = 10, m = 5, u = 1, k = 1)

MEDIUM

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Work, Energy and Power>JEE Main - 2nd April 2017>Q 77

A time dependent force

F = 6 t

acts on a particle of mass

1 kg

. If the particle starts from the rest, the work done by the force during the first

1 \sec

will be:

MEDIUM

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Work, Energy and Power>JEE Main - 2nd April 2017>Q 78

A body of mass

m = 10^{- 2} kg

is moving in a medium and experiences a frictional force

F = - k v^{2} .

Its initial speed is

v_{0} = 10 m s^{- 1} .

After

10 s

its kinetic energy is

\frac{1}{8} m v_{0}^{2},

then value of

k

will be:-

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Work, Energy and Power>JEE Main - 8th April 2017>Q 79

An object is dropped from a height

h

from the ground. Every time it hits the ground it loses

50 %

of its kinetic energy. The total distance covered as

t \to \infty

is:

HARD

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Work, Energy and Power>JEE Main - 9th April 2017>Q 80

Two particles

A

and

B

of equal mass

M

are moving with the same speed

v

as shown in figure. They collide completely inelastic and move as a single particle

C

. The angle

θ

that the path of

C

makes with the

X

-axis is given by-

Question Image

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JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Work, Energy and Power>JEE Main - 9th April 2016>Q 81

A car of weight W is on an inclined road that rises by 100 m over a distance of 1km and applies a constant frictional force

\frac{W}{20}

on the car. While moving uphill on the road at a speed of

10 m s^{- 1}

, the car needs power P. If it needs power

\frac{P}{2}

while moving downhill at speed

υ

then value of

υ

is:

MEDIUM

JEE Main

IMPORTANT

EMBIBE CHAPTER WISE PREVIOUS YEAR PAPERS FOR PHYSICS>Chapter 4 - Work, Energy and Power>JEE Main - 3rd April 2016>Q 82

A person trying to lose weight by burning fat lifts a mass of 10 kg upto a height of 1m 1000 times. Assume that the potential energy lost each time he lowers the mass is dissipated. How much fat will he use up considering the work done only when the weight is lifted up? Fat supplies

3.8 \times 10^{7}

J of energy per kg which is converted to mechanical energy with a 20% efficiency rate. Take

g = 9.8 m s^{- 2}

It is found that if a neutron suffers an elastic collinear collision with a deuterium at rest, the fractional loss of its energy is Pd, while for its similar collision with a carbon nucleus at rest, the fractional loss of energy is Pc. The values of Pd and Pc are respectively

Important Questions on Work, Energy and Power

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It is found that if a neutron suffers an elastic collinear collision with a deuterium at rest, the fractional loss of its energy is $P_{d}$ , while for its similar collision with a carbon nucleus at rest, the fractional loss of energy is $P_{c}$ . The values of $P_{d}$ and $P_{c}$ are respectively