CBSE Questions for Class 9 Physics Work And Energy Quiz 10 - MCQExams.com

Calculate the work done by the person to push a box with a force of $$20 N$$ over a distance of $$8.0 m$$ in the direction of the force?
  • $$1.6 J$$
  • $$16 J$$
  • $$160 J$$
  • $$1600 J$$
  • $$16000 J$$
Identify the wrong statement about work.
  • It is the scalar product of force and displacement
  • It is a vector that is always in the same direction as the force.
  • It is measured in joules.
  • It has the same units as energy.
How much work does a person do in pushing a box with a force of 10 N over a distance of 8.0 m in the direction of the force? 
  • 0.8 J
  • 8.0 J
  • 80 J
  • 800 J
  • 8000 J
Which of the following is NOT a unit of energy?
  • Watt
  • eV
  • Kilowatt hour
  • Joule
  • Calorie
Identify the best definition of energy?
  • anything that has mass and takes up space
  • distance moved in a period of time
  • ability to do work
  • mode of opperation
  • moment of an object with application of force
A body of mass 6 kg is under a force of 6 N which causes displacement in it given by $$S =\frac{t^2}{4}$$ where 't' is time in seconds. The work done by the force in 2 s is:
  • 12 J
  • 9 J
  • 6 J
  • 3 J
Person $$A$$ stands on the right side of a cart, while Person $$B$$ stands on the left side. The cart is initially at rest. Person $$A$$ pushes on the cart with a force of $$22.0 N$$, and Person $$B$$ pushes on the cart with a force of $$33.0 N$$.
The cart, with no other forces acting on it, starts to move and rolls through a distance of $$2.0 m$$ while both people continue to push with their respective forces.
How much work was done on the cart by Person $$B$$?
  • $$-44.0 J$$
  • $$+22.0 J$$
  • $$+44.0 J$$
  • $$+66.0 J$$
  • None of the above
Define one watt:
  • one joule per second
  • one second per joule
  • ten joules per second
  • voltage divided by current
  • resistance multiplied by voltage
A block of mass 10 kg is pulled by a constant horizontal force of 19 N and it is displaced by 15 m across the floor. Calculate the work done.
  • 1.3 J
  • 30 J
  • 285 J
  • 5586 J
  • 1J
How much work does a person do in pushing a box with a force of $$20\ N$$ over a distance of $$8.0\ m$$ in the direction of the force? 
  • $$1.6\ J$$
  • $$16\ J$$
  • $$160\ J$$
  • $$1600\ J$$
  • $$16000\ J$$
Does the Law of Conservation of energy apply to machines?
  • No, as machines require a constant input of energy in order to work
  • Yes, the energy required to maintain motion is balanced by the energy lost to friction
  • No, as machines can create energy from motion
  • Yes, but only to perpetual motion machines
  • No, as the law would apply to only perpetual motion machines
Identify which of the following option best describe work.
  • a form of energy
  • measured in Coulombs
  • the potential charge of a particle
  • equal to the voltage
  • the same for all charge collections
A man with a box on his head is climbing up a ladder. What work is said to be done by the man on the box?
  • Positive
  • Negative
  • Zero
  • Undefined
A $$3.0\ N$$ force applied on a $$0.40\ kg$$ mass makes the mass move at a constant speed of $$3.0\ {m}{s^{-1}}$$, held back by friction. In the span of it moving through $$4.0\ m$$, the net work done on the mass is:
  • $$0\ J$$
  • $$0.90\ J$$
  • $$12\ J$$
  • $$-12\ J$$
  • $$-0.90\ J$$
When a stone tied to a string is whirled in a circle, what kind of work is said to be done on it by the string?
  • Positive
  • Negative
  • Zero
  • Undefined
SI unit of energy is  _________ .
  • newton
  • joule
  • erg
  • metre
The running water primarily possesses potential energy.
  • True
  • False
Find the work done by a force of $$5 N$$ in displacing a book through $$20 cm$$ along the direction of the force.
  • $$1 J$$
  • $$3 J$$
  • $$4 J$$
  • $$5 J$$
How much work is done in ergs in pulling a box $$2\ m$$ across a tabletop with a force of $$20\ N$$ in the horizontal direction?
  • $$40$$
  • $$4000$$
  • $$4\times 10^7$$
  • $$40\times 10^7$$
1 horse power is equal to ______ watt :
  • 746
  • 500
  • 646
  • 700
A boy carrying a box on his head is walking on a level road from one place to another. The boy is doing no work.
  • True
  • False
An air conditioner is rated 240 V, 1.5 kW. The air conditioner is switched on 8 hours each day. What is electrical energy consumed in 30 days?
  • 360 kWh
  • 2.88 kWh
  • 120 kWh
  • 240 kWh
The correct formula to find the velocity of a body with kinetic energy '$$k$$' is:
  • $$V=\dfrac{2k}{m}$$
  • $$V=\sqrt{\dfrac{2k}{m}}$$
  • $$V=\dfrac{4{k}^{2}}{m}$$
  • $$V=\dfrac{1}{2}km$$
A $$2kg$$ object is moving at $$3m/s$$. A $$4N$$ force is applied in the direction of motion and then removed after the object has travelled an additional $$5m$$. The work done by this force is:
  • $$10 J$$
  • $$15 J$$
  • $$20 J$$
  • $$25 J$$
$$1$$ kilowatt hr $$=$$ __________ joules.
  • $$10.6 \times {10}^{6}$$
  • $$3.6 \times {10}^{6}$$
  • $$30.6 \times {10}^{6}$$
  • $$3.6 \times {10}^{5}$$
$$1 Wh$$ (Watt hour) is equal to :
  • $$36\times { 10 }^{ 5 }J$$
  • $$36\times { 10 }^{ 4 }J$$
  • $$3600 J$$
  • $$3600 { Js }^{ -1 }$$
Kinetic energy of a body depends upon its:
  • mass
  • velocity
  • density 
  • both A and B
  • Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
  • Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
  • Assertion is incorrect but Reason is correct
  • Both Assertion and Reason are incorrect
A bicyclist comes to a skidding stop in $$10 m$$. During this process, the force on the bicycle due to the road is $$200N$$ and is directly opposed to the motion. The work done by the cycle on the road is
  • $$+ 2000J$$
  • $$200J$$
  • $$zero$$
  • $$20,000J$$
A block of weight $$W$$ is pulled a distance $$l$$ along a horizontal table. The work done by the weight is 
  • $$Wl$$
  • $$Wgl$$
  • $$Wl/g$$
  • zero
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