✕
  1. Tardigrade
  2. Question
  3. Physics
  4. A man throws the bricks to a height of 12 m where they reach with a speed of 12 m / s. If he throws the bricks such that they just reach that height, what percentage of energy will be saved: ( Take g =9.8 m / s 2 )

Q. A man throws the bricks to a height of where they reach with a speed of . If he throws the bricks such that they just reach that height, what percentage of energy will be saved : ( Take )

Work, Energy and Power Report Error

Solution:

Case-I.

Let speed with which the ball is thrown up is



Case-II.




energy charge

Negative sign shows that energy is saved.

Questions from Work, Energy and Power

1. The work done by a particle moving with a velocity of (where c is the velocity of light) in empty space free of electromagnetic field and far away from all matter is:

Manipal 2008

2. The machine gun fires bullets per minute. If the mass of each bullet is and the velocity of the bullets is ,the power (in )of the gun is

NTA Abhyas 2020

3. A body constrained to move along Z-axis of a coordinate system is subjected to a constant force given by where , and are the unit vector along the X, Y and Z-axis of the system respectively. What is the work done by this force in moving the body a distance of along the Z-axis?

NTA Abhyas 2020

4. A particle of mass is moving in a circular path of constant radius such that its centripetal acceleration is varying with time as , where is a constant. The power delivered to the particle by the force acting on it is

NTA Abhyas 2020

5. A ball of mass collides with a wall with speed and rebounds on the same line with the same speed. If mass of the wall is taken as infinite, the work done by the ball on the wall is

Physics Most Viewed Questions

1. If and respectively denote energy and gravitational constant, then has the dimensions of:

NEET 2021 Physical World, Units and Measurements

2. The de Broglie wavelength of an electron moving with kinetic energy of is nearly

NEET 2020 Dual Nature of Radiation and Matter

3. A car starts from rest and accelerates at At , a ball is dropped out of a window by a person sitting in the car. What is the velocity and acceleration of the ball at ? (Take

NEET 2021 Motion in a Straight Line

4. A wheel with metallic spokes each long is rotated with a speed of in a plane perpendicular to a magnetic field of . The induced emf between the axle and rim of the wheel will be,

NEET 2020 Electromagnetic Induction

5. A barometer is constructed using a liquid (density What would be the height of the liquid column, when a mercury barometer reads ?
(density of mercury

NEET 2020 Mechanical Properties of Fluids

Latest Updates