The law of conservation of energy - class-VIII
Description: the law of conservation of energy | |
Number of Questions: 31 | |
Created by: Niharika Sharma | |
Tags: mechanics work, energy and power energy and its forms energy transformations and energy transfers work and energy types of energy physics work, energy and machines |
The law of conservation of energy implies that the:
Energy conservation law says that:
The speed of a car of mass 1000 kg is reduced from 20 m/s to 10 m/s. What is the work done by the brakes of the car?
When a stone falls freely towards the earth, its total energy ?
In which one of the following is electrical energy is converted to light energy?
A steam engine converts
When an object falls freely towards the earth, then its total energy :
According to law of conservation of energy :
What is law of conservation of energy?
When you push a huge rock with all your might and fail to move it,then:
State whether the given statement is True or False :
A freely falling object eventually stops on reaching ground. What happens to its potential and kinetic energy while falling?
State whether the given statement is True or False :
When a pendulum oscillates, it comes to rest after sometime because :
Find energy in kWh consumed in 10 hours by four devices of power 500W each?
Does the Law of Conservation of energy apply to machines?
Based on the Law of Energy Conservation, which of the following would best maintain a machine's ability to do work without input of additional energy?
A tennis ball dropped from a height of 2 m rebounds only 1.5 m after hitting the ground. What fraction of energy is lost in the impact?
According to the law of conservation of energy, total energy is
Before a rubber ball bounces off from the floor, the ball is in contact with the floor for a fraction of second. Which of the following statements are correct?
According to law of conservation of energy the total energy of the universe is:
According to the law of conservation of energy.
The temperature of water at the bottom of a large waterfall is higher than that of the water at the top, because
Law of conservation of energy states that :
A thorium nucleus emits an alpha particle. Which of the following fundamental physics principles can be used to explain why the direction of the daughter nucleus recoil must be in the opposite direction of the alpha emission?
I. Newtons third law
II. Conversation of momentum
III. Conversation of energy
A ball is dropped from a height of $10\ m$. If the energy of the ball reduces by $40\%$ after striking the ground, how much high can the ball bounce back? $(g = 10 m s^{-2})$ :
A stone of mass $m$ kg is whirled in a vertical circle of radius $20$ cm. The difference in the kinetic energies at the lowest and the topmost position is:
If 0.5 of any substance is completely transformed into energy, then how much energy in kilo-joule will be obtained?
A domestic gas cylinder contains about 14.2 kg of LPG. A strong smelling substance called ethyl mercaptan is added to the LPG to detect the leakage of gas from the cylinder. On being lighted, it burs with a blue flame. One gram of LPG produces about 50 kJ of heat. Weight of the domestic cylinder is -
According to the law of conservation of energy:
According to law of conservation of energy :