FBISE, NCP & NBF-aligned resources for Classes 9–12
Browse by Class
Browse by Type
Physics Chapter 5 : Topic 4
Work–Energy Theorem in Resistive Media
1 / 36
The work-energy theorem states that the net work done on an object is equal to:
Reasoning: According to the theorem: $\mathbf{W}_{\mathbf{net}}\mathbf{= \Delta\ }\mathbf{K\ .E}\mathbf{=}\mathbf{K\ .E}_{\mathbf{\ f}}\mathbf{-}\mathbf{K\ .E}_{\mathbf{\ i}}$
2 / 36
If the net work done on an object is positive, its kinetic energy:
Reasoning: Positive work adds energy to the object.
3 / 36
The unit of work and kinetic energy is:
Reasoning: Both work and energy are measured in joules.
4 / 36
According to the work-energy theorem:
Reasoning: Net work causes a change in kinetic energy.
5 / 36
If the velocity of an object increases, the net work done on it is:
Reasoning: $\mathbf{W}_{\mathbf{net}}\mathbf{=}\mathbf{K\ .E}_{\mathbf{\ f}}\mathbf{-}\mathbf{K\ .E}_{\mathbf{\ i}}$ ; Increasing $\mathbf{K\ .E}$ means positive work.
6 / 36
A resistive force is a force that:
Reasoning: Resistive forces oppose displacement.
7 / 36
Which of the following is a resistive force?
Reasoning: Friction opposes motion and dissipates energy.
8 / 36
In a resistive medium, some mechanical energy is converted into:
Reasoning: Resistance converts mechanical energy into thermal energy.
9 / 36
When friction acts on a moving object, the work done by friction is:
Reasoning: Friction acts opposite to displacement.
10 / 36
Air resistance affects a moving object by:
Reasoning: Air resistance removes mechanical energy.
11 / 36
A block moving on a rough surface slows down because:
Reasoning: Negative work by friction decreases kinetic energy.
12 / 36
A body has initial kinetic energy of $\mathbf{500\ J}$. Friction does $\mathbf{200\ J}$ negative work. Final kinetic energy is:
Reasoning: $\mathbf{K\ .E}_{\mathbf{\ f}}\mathbf{=}\mathbf{K\ .E}_{\mathbf{\ i}}\mathbf{+ W = 500 - 200 = 300\ J}$
13 / 36
A car moving on a rough road stops after traveling some distance. The lost kinetic energy is equal to:
Reasoning: Friction removes kinetic energy.
14 / 36
A$\mathbf{\ }\mathbf{2\ kg}$ object moving at $\mathbf{10\ m/s}$ has kinetic energy:
Reasoning: $\mathbf{K\ .E}\mathbf{=}$ $\frac{\mathbf{1}}{\mathbf{2}}\mathbf{m}\mathbf{v}^{\mathbf{2}}\mathbf{=}\frac{\mathbf{1}}{\mathbf{2}}\mathbf{(2)(100) = 100\ J}$
15 / 36
If friction removes all kinetic energy of a moving object, the final velocity becomes:
Reasoning: Zero kinetic energy means zero velocity.
16 / 36
A $\mathbf{5\ kg}$ object moving at $\mathbf{4\ m/s}$ stops due to friction. The work done by friction is:
Reasoning: Initial $\mathbf{K\ .E}$: $\mathbf{K\ .E}\mathbf{=}$ $\frac{\mathbf{1}}{\mathbf{2}}\mathbf{(5)(}\mathbf{4}^{\mathbf{2}}\mathbf{) = 40\ J}$Friction removes this energy: $\mathbf{W = - \ 40\ J}$
17 / 36
A force does $\mathbf{300\ J}$ work on an object initially having $\mathbf{200\ J}$ kinetic energy. Final kinetic energy is:
Reasoning: $\mathbf{K\ .E}_{\mathbf{\ f}}\mathbf{=}\mathbf{K\ .E}_{\mathbf{\ i}}\mathbf{+ W = 200 + 300 =}\mathbf{500\ J}$
18 / 36
A $\mathbf{1000\ kg}$ car slows from $\mathbf{20\ m/s}$ to $\mathbf{10\ m/s}$ due to resistance. The work done by resistance is:
Reasoning: Resistance reduces kinetic energy.
19 / 36
A machine does $\mathbf{500\ J}$ work against friction. The energy lost is:
Reasoning: Work against friction equals energy dissipated.
20 / 36
A ball moving through air slows down because:
Reasoning: Air resistance opposes motion.
21 / 36
A person pushes a box on a rough floor. The net work done is:
Reasoning: Network includes all forces acting on the object.
22 / 36
When a car brakes suddenly, the kinetic energy changes into:
Reasoning: Brakes use friction to convert $\mathbf{K\ .E}$ into heat.
23 / 36
If resistive force increases, the stopping distance of a moving object:
Reasoning: Greater resistance removes kinetic energy faster.
24 / 36
A parachute slows a falling person because:
Reasoning: Increased drag reduces kinetic energy.
25 / 36
A body moving with constant speed on a rough horizontal surface has:
Reasoning: Constant speed means constant kinetic energy. $\mathbf{\Longrightarrow}$ $\mathbf{\Delta\ }\mathbf{K\ .E}\mathbf{= 0}$
26 / 36
A force-displacement graph for resistance is below the displacement axis. The work done is:
Reasoning: Area below axis represents negative work.
27 / 36
A projectile moving through air has less range than in vacuum because:
Reasoning: Air resistance removes energy from the projectile.
28 / 36
The total work done on an object in a resistive medium is:
Reasoning: Net work includes every force acting.
29 / 36
If the net work done on an object is zero, then:
Reasoning: $\mathbf{W}_{\mathbf{net}}\mathbf{= \Delta\ }\mathbf{K\ .E}\mathbf{= 0}$
30 / 36
A falling object reaches terminal velocity because:
Reasoning: At terminal velocity, net force becomes zero.
31 / 36
A truck and a car experience the same resistive force. The one with greater kinetic energy will:
Reasoning: More kinetic energy requires more work to stop.
32 / 36
The work done by friction depends on:
Reasoning: Frictional work: $\mathbf{W = Fs}$
33 / 36
In a resistive medium, mechanical energy:
Reasoning: Resistance dissipates mechanical energy.
34 / 36
The work-energy theorem is valid:
Reasoning: It applies to net work by all forces.
35 / 36
When a moving object stops due to friction, the work done by friction equals:
Reasoning: $\mathbf{W}_{\mathbf{f}}\mathbf{= 0 -}\mathbf{K\ .E}_{\mathbf{\ i}}\mathbf{= - \ }\mathbf{K\ .E}_{\mathbf{\ i}}$
36 / 36
A force acting opposite to motion causes:
Reasoning: Opposite forces perform negative work.
Your score is
Restart quiz
