Tag: substances, objects and energy

Quizzes (5) Questions (175)

Questions Related to substances, objects and energy

Multiple choice evs solar energy renewable and non-renewable resources renewable and non-renewable sources of energy substances, objects and energy solar power plant production of electricity from solar energy solar energy and its applications

The fossil fuels include:

  1. Uranium

  2. Soil

  3. Natural gas

  4. Plants
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Fossil fuels are formed when plants and marine species are buried below ground and are subjected to immense pressure and temperature for thousands of years. Examples include coal, petroleum and natural gas.

Multiple choice physics types of energy renewable and non-renewable resources renewable and non-renewable sources of energy substances, objects and energy

A body is falling freely under the action of gravity alone in vacuum. Which of the following quantities remain constant during the fall?

  1. Kinetic energy

  2. Potential energy

  3. Total mechanical energy

  4. Total linear momentum
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
As the body is falling freely under gravity, the potential energy decreases continuously and kinetic energy increases continuously as all the conservative forces are doing work. So, total mechanical energy $(PE + KE)$ of the body will be constant.
At point A total mechanical energy will be $EA = K.E + P.E$
$E _{A}=\dfrac{1}{2}mv^{2}+m _{g}H$
As velocity will be zero at $A$, so its kinetic energy will be zero 
$E _{A}=M _{g}H$
Velocity at point $B$ will be 
$V _{B}=\sqrt{2gh}$
So energy at point $B$ will be 
$E _{B}=KE+PE$
$E _{B}=\dfrac{1}{2}m(2gh)+mg(H-h)$
$E _{B}=mgh+mgH-mgh$
$E _{B}=mgH$
Now velocity at point $C$ will be 
$V _{C}=\sqrt{2gh}$
So energy at point $C$ will be
$ E _{C}=KE+PE$
$E _{C}=\dfrac{1}{2}m(2gH)+mg(0)$
So, total mechanical energy will remain same (if we neglect the air friction).
Multiple choice physics types of energy renewable and non-renewable resources renewable and non-renewable sources of energy substances, objects and energy

While falling

  1. Potential energy

  2. Kinetic energy

  3. Both A & B

  4. None
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

While it is falling it has certain velocity,as kinetic energy is defined as the virtue of its state of motion it will have kinetic energy.As it is at certain height it will have Potential energy which is defined by virtue of state of its position.Hence ball has both potential and kinetic energy.

Multiple choice physics types of energy renewable and non-renewable resources renewable and non-renewable sources of energy substances, objects and energy

A body rolling down a hill has

  1. K.E. only

  2. P.E. only

  3. Neither K.E. nor P.E

  4. Both (a) and (b)
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

While rolling down from hill a body will have some Potential energy due to height wrt to ground and due to rolling it will have some Kinetic energy .As it will keep rolling down , Its PE will change into KE

So $E _{Total}=mgh+\dfrac{mv^2}{2}$

Multiple choice physics types of energy renewable and non-renewable resources renewable and non-renewable sources of energy substances, objects and energy

A flying aeroplane has:

  1. only potential energy

  2. only kinetic energy

  3. both potential and kinetic energy

  4. none of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

An flying aeroplane required some work to be done against gravity to go upto that much height that work will be stored as potential energy of the body. Also aeroplane has some mass and moving with some velocity so has some kinetic energy also. 

So this poses both potential as well as kinetic energy.

Multiple choice physics types of energy renewable and non-renewable resources renewable and non-renewable sources of energy substances, objects and energy

A body rolling down a hill has:

  1. K.E. only

  2. P.E. onley

  3. neither K.E. and P.E.

  4. both K.E and P.E
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Taking toe of the hill as refrence point so some work against the gravity is done to raise the body to top of the hill so it poses some potential energy equal to mgh where m is mass and g is acceleration due to gravity and h is vertical height.

Also he is moving so he must have some kinetic energy.
So body rolling along the hill have both kinetic as well as potential energy.

Multiple choice physics types of energy renewable and non-renewable resources renewable and non-renewable sources of energy substances, objects and energy

Which of the following has both kinetic energy and potential energy ?

  1. A flying bird

  2. A bent bow about to shoot an arrow

  3. An athlete running at full speed

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Since the bird is flying is must be at some distance from the ground and Potential energy is present when there is some height associated with that object (Since P.E = mgh). Also  the bird has mass and thus gravity will be acted on it. Kinetic energy is present for an object if it has velocity.This a flying bird has both kinetic energy and potential energy.

Multiple choice physics types of energy renewable and non-renewable resources renewable and non-renewable sources of energy substances, objects and energy

Identify an example of kinetic mechanical energy?

  1. A loaded gun

  2. A set mouse trap

  3. An elevated wrecking ball

  4. A compressed spring

  5. A bike rolling down a hill
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

A loaded gun, a set mouse trap and a compressed spring are examples of elastic potential energy.

An elevated wrecking ball is an example of gravitational potential energy.
A bike rolling down a hill is an example of kinetic energy, where potential energy is constantly converting in the kinetic energy of the bike as given by $\dfrac{1}{2}mv^2$.