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Final Assessment: Work, Energy and Simple Machines

Section A: Work and Power

Question 1mcq
Which option correctly completes this statement: For scientific work to be done on an object, a force must cause?
A.Only effort without movement
B.Only passage of time
C.Displacement of the object
D.Only tiredness of the person
Question 2mcq
A force of 20 N20\,N moves a body by 4 m4\,m in the direction of the force. How much work is done?
A.5 J5\,J
B.20 J20\,J
C.24 J24\,J
D.80 J80\,J
Question 3mcq
Which SI unit is used to measure power?
A.watt
B.joule
C.newton
D.metre
Question 4mcq
If 200 J200\,J of work is done in 10 s10\,s, what is the power developed?
A.10 W10\,W
B.20 W20\,W
C.210 W210\,W
D.2000 W2000\,W

Section B: Energy and Conservation

Question 5mcq
What is the SI unit of energy?
A.newton
B.watt
C.hertz
D.joule
Question 6mcq
In a microphone, sound energy is converted mainly into which form of energy?
A.Gravitational energy
B.Nuclear energy
C.Electrical energy
D.Elastic energy only
Question 7mcq
The work-energy theorem states that the work done by the net force on a body is equal to the change in its?
A.Mass number
B.Kinetic energy
C.Frequency only
D.Electric potential difference
Question 8mcq
Which statement best describes kinetic energy?
A.Energy stored because of height
B.Energy stored in chemical bonds only
C.Energy possessed by a moving object
D.Energy possessed only by objects at rest
Question 9mcq
A 4 kg4\,kg object is moving with a speed of 5 m/s5\,m/s. What is its kinetic energy?
A.10 J10\,J
B.20 J20\,J
C.50 J50\,J
D.100 J100\,J
Question 10mcq
A book kept on a high shelf mainly has which type of mechanical energy due to its position?
A.No energy
B.Heat energy only
C.Sound energy only
D.Gravitational potential energy
Question 11mcq
A 2 kg2\,kg object is raised to a height of 5 m5\,m. Taking g=10 m/s2g=10\,m/s^2, what is its gravitational potential energy?
A.10 J10\,J
B.50 J50\,J
C.100 J100\,J
D.200 J200\,J
Question 12mcq
Which option correctly completes this statement: According to the law of conservation of energy, the total energy of an isolated system?
A.Only decreases
B.Only increases
C.Remains constant
D.Is completely destroyed

Section C: Simple Machines

Question 13mcq
A ramp used to push a heavy box into a truck is an example of which simple machine?
A.Wheel and axle
B.Lever
C.Pulley
D.Inclined plane
Question 14mcq
A machine lifts a load of 60 N60\,N using an effort of 20 N20\,N. What is its mechanical advantage?
A.0.33
B.3
C.40
D.80
Question 15mcq
To test how the effort needed to lift a load changes with the length of an inclined plane, which experimental plan is the fairest?
A.Take no measurements and only observe
B.Change the load and ramp length together
C.Change only the ramp length and keep the load same
D.Change the labels on the apparatus
Question 16mcq
When an archer pulls back the string of a bow and holds it stretched, which form of energy is mainly stored in the bow?
A.Nuclear energy
B.Kinetic energy
C.Elastic potential energy
D.Sound energy