Get a free home demo of LearnNext

Available for CBSE, ICSE and State Board syllabus.
Call our LearnNext Expert on 1800 419 1234 (tollfree)
OR submit details below for a call back

clear
Finding exercises tough? Install LearnNext+ app to watch our videos and get a crystal clear understanding of concepts Install Now X
X
learnnextPlus

Install the app to watch our videos and get a crystal clear understanding of concepts

Install Now
searchtune
What people are asking?

Tuba

Jun 13, 2014

It is easier to pull  a lawn roller than to push it. Explain using the resolution of forces. 

This answer has an image. Please click on the question to read more.

Answer (4)

Rk sharma

Mar 6, 2015

A body cools from 80 °C to 50 °C in 5 minutes.  Calculate the time it takes to cool from 60°C to 30 °C.  The temprature of the surroundings is 20°C. 

According to Newton's law of cooling, we have

mc (T1 - T2)/t = k [(T1 + T2)/2   -  T0)]        -----------...

Answer (1)

Amarnathreddy M

Feb 3, 2014

A ball is dropped from rest at a height of 12 m. If it loses 25% of its kinetic energy on striking the ground, what is the height to which it bounces? How do your account for the loss in kinetic energy?

Solution:
Given a ball is at a height (h) of 12m 
When a body at certain height poses maximum potential energy which converted into kinetic energy when a  ball just before...

Answer (2)

Sanalkumar S

Mar 10, 2015

A car of mass 1000 kg moving with velocity of 30 m/s collides with the back of a stationry lorry of mass 9000 kg. Calculate the speed of vehicle immediatly after the collision if they remain jammed together.

Given:
Mass of the car (m1)= 1000 kg
Initial velocity of the car (u1 )= 30 m/s
Mass of the lorry (m2)= 9000 kg
Initial...

Answer (2)

Dinesh

Jan 16, 2015

The work done by a spring force : (1) is always negative (2) is always positiv..

Spring force F = − kx (Hooke's law)

The minus sign indicates that the spring force is always opposite in direct...

Answer (1)

Navaneeth K

Oct 19, 2014

CAN anyone answer Question 6.15 in NCERT text book. i cannot understand the method of solution used in learnnext solved exercise.

A pump on the ground floor of a building can pump up water to fill a tank of volume 30m cube in 15 minutes.if the tank is 40 m above the ground,and efficiency of pump is 30%,how much electric power is consumed by the pump?

Volume of water = 30 m3.

Answer (1)

Tuba

Feb 6, 2015

A stone is dropped from a height h.Prove that the total mechanical energy at any point in its path is mgh. 

This answer has an image. Please click on the question to read more.

Answer (2)

Amarnathreddy M

Feb 3, 2014

A solid sphere of mass 1 kg and radius 0.1 m rolls without slipping at a uniform velocity of

1 m.s-1 along a straight line on a horizontal floor. What is the kinetic energy of the sphere?

This answer has an image. Please click on the question to read more.

Answer (2)

Dinesh

Jan 16, 2015

Two bodies having masses m1 and m2 and velocities u1 and u2 collide and form a composite system. If m1+ m2= 0 (m1≠ m2), th..

Given:  m1u+  m2u = 0
Initial momentum = Final momentum
⇒ m1u

Answer (2)

Sanalkumar S

Mar 17, 2015

Why the work done by centripetal force is zero?

We know that
Work, W = F. S Cos θ.

As the centripetal force is perpendicular to the dispalcement   = 90 0

⇒ 

Answer (1)

Tuba

Jun 13, 2014

It is easier to pull  a lawn roller than to push it. Explain using the resolution of forces. 

This answer has an image. Please click on the question to read more.

Answer (4)

Rk sharma

Mar 6, 2015

A body cools from 80 °C to 50 °C in 5 minutes.  Calculate the time it takes to cool from 60°C to 30 °C.  The temprature of the surroundings is 20°C. 

According to Newton's law of cooling, we have

mc (T1 - T2)/t = k [(T1 + T2)/2   -  T0)]        -----------...

Answer (1)

Amarnathreddy M

Feb 3, 2014

A ball is dropped from rest at a height of 12 m. If it loses 25% of its kinetic energy on striking the ground, what is the height to which it bounces? How do your account for the loss in kinetic energy?

Solution:
Given a ball is at a height (h) of 12m 
When a body at certain height poses maximum potential energy which converted into kinetic energy when a  ball just before...

Answer (2)

Sanalkumar S

Mar 10, 2015

A car of mass 1000 kg moving with velocity of 30 m/s collides with the back of a stationry lorry of mass 9000 kg. Calculate the speed of vehicle immediatly after the collision if they remain jammed together.

Given:
Mass of the car (m1)= 1000 kg
Initial velocity of the car (u1 )= 30 m/s
Mass of the lorry (m2)= 9000 kg
Initial...

Answer (2)

Dinesh

Jan 16, 2015

The work done by a spring force : (1) is always negative (2) is always positiv..

Spring force F = − kx (Hooke's law)

The minus sign indicates that the spring force is always opposite in direct...

Answer (1)

Navaneeth K

Oct 19, 2014

CAN anyone answer Question 6.15 in NCERT text book. i cannot understand the method of solution used in learnnext solved exercise.

A pump on the ground floor of a building can pump up water to fill a tank of volume 30m cube in 15 minutes.if the tank is 40 m above the ground,and efficiency of pump is 30%,how much electric power is consumed by the pump?

Volume of water = 30 m3.

Answer (1)

Tuba

Feb 6, 2015

A stone is dropped from a height h.Prove that the total mechanical energy at any point in its path is mgh. 

This answer has an image. Please click on the question to read more.

Answer (2)

Amarnathreddy M

Feb 3, 2014

A solid sphere of mass 1 kg and radius 0.1 m rolls without slipping at a uniform velocity of

1 m.s-1 along a straight line on a horizontal floor. What is the kinetic energy of the sphere?

This answer has an image. Please click on the question to read more.

Answer (2)

Dinesh

Jan 16, 2015

Two bodies having masses m1 and m2 and velocities u1 and u2 collide and form a composite system. If m1+ m2= 0 (m1≠ m2), th..

Given:  m1u+  m2u = 0
Initial momentum = Final momentum
⇒ m1u

Answer (2)

Sanalkumar S

Mar 17, 2015

Why the work done by centripetal force is zero?

We know that
Work, W = F. S Cos θ.

As the centripetal force is perpendicular to the dispalcement   = 90 0

⇒ 

Answer (1)

Filters