FBISE, NCP & NBF-aligned resources for Classes 9–12
Browse by Class
Browse by Type
Physics Chapter 3 : Topic 5
Momentum and Kinetic Energy in Collisions
1 / 35
In a closed system with no external force, which quantity is always conserved?
Reasoning: The total momentum of a closed system remains constant when no external force acts on it.
2 / 35
Why is momentum conserved in a closed system?
Reasoning: Internal forces occur in equal and opposite pairs (Newton's Third Law), so total momentum remains unchanged.
3 / 35
During an inelastic collision, momentum is conserved but kinetic energy:
Reasoning: Some kinetic energy is transformed into heat, sound, or deformation.
4 / 35
Which statement best explains why momentum can remain constant while kinetic energy changes?
Reasoning: Conservation of momentum does not necessarily imply conservation of kinetic energy because they depend differently on velocity.
5 / 35
Which quantity depends on the square of velocity?
Reasoning: $\mathbf{K\ .E\ =}$ $\frac{\mathbf{1}}{\mathbf{2}}\mathbf{\ m}\mathbf{v}^{\mathbf{2}}$, making kinetic energy more sensitive to velocity changes.
6 / 35
A collision in which objects stick together after impact is:
Reasoning: Sticking together is the defining feature of a perfectly inelastic collision.
7 / 35
In a perfectly inelastic collision, which quantity remains conserved?
Reasoning: Momentum remains conserved, but kinetic energy decreases.
8 / 35
Kinetic energy lost during a collision is usually converted into:
Reasoning: Energy is transformed into other forms rather than disappearing.
9 / 35
Which collision conserves both momentum and kinetic energy?
Reasoning: Elastic collisions conserve both quantities.
10 / 35
A truck and a car collide. The system momentum remains constant because:
Reasoning: Momentum conservation results from negligible external forces.
11 / 35
If the total momentum before a collision is zero, the total momentum after collision is:
Reasoning: Conservation of momentum requires it to remain zero.
12 / 35
Which quantity can change even when momentum remains constant?
Reasoning: Kinetic energy may be converted into other forms.
13 / 35
Why does kinetic energy decrease in an inelastic collision?
Reasoning: Total energy is conserved; only its form changes.
14 / 35
Which statement is TRUE about kinetic energy in collisions?
Reasoning: Only elastic collisions conserve total kinetic energy.
15 / 35
Which quantity is a vector?
Reasoning: Momentum has both magnitude and direction.
16 / 35
Which quantity is scalar?
Reasoning: Kinetic energy has magnitude only.
17 / 35
Two equal masses move with equal speeds in opposite directions. Their total momentum is:
Reasoning: Opposite momenta cancel each other.
18 / 35
Two equal masses move with equal speeds in opposite directions, the total kinetic energy is:
Reasoning: Kinetic energy is scalar and always positive.
19 / 35
Which observation directly indicates loss of kinetic energy during collision?
Reasoning: Heat and sound indicate conversion of kinetic energy.
20 / 35
A rubber ball rebounds from the floor. The collision is not perfectly elastic because:
Reasoning: Real collisions always involve some energy loss.
21 / 35
Why is momentum conservation considered more universal than kinetic energy conservation?
Reasoning: Momentum remains conserved regardless of collision type.
22 / 35
A collision occurs in a closed system. Which statement must be true?
Reasoning: Momentum conservation always applies to closed systems.
23 / 35
The reason kinetic energy may change while momentum remains conserved is mainly because:
Reasoning: The different mathematical dependence allows $\mathbf{K\ .E}$ to change even when momentum is conserved.
24 / 35
A bullet embeds itself in a wooden block. This is an example of:
Reasoning: The bullet and block move together after collision.
25 / 35
During a perfectly inelastic collision, kinetic energy:
Reasoning: Some kinetic energy converts into internal energy.
26 / 35
If kinetic energy is conserved, the collision must be:
Reasoning: Conservation of kinetic energy is the hallmark of elastic collisions.
27 / 35
Which of the following can be conserved simultaneously in an elastic collision?
Reasoning: Elastic collisions conserve both momentum and kinetic energy.
28 / 35
In a collision, the total momentum before impact is $\mathbf{100\ kg\ m/s}$. What is the total momentum after impact?
Reasoning: Momentum is conserved in a closed system.
29 / 35
Which factor determines whether kinetic energy changes during a collision?
Reasoning: Elastic and inelastic collisions differ in kinetic energy conservation.
30 / 35
A moving object strikes a soft clay surface and stops. The loss of kinetic energy is mainly due to:
Reasoning: The kinetic energy transforms into internal energy and deformation.
31 / 35
Which statement is FALSE?
Reasoning: Kinetic energy is not conserved in inelastic collisions.
32 / 35
An explosion occurs in an isolated system. The total momentum of fragments is:
Reasoning: Internal forces cannot change total momentum.
33 / 35
Why can an explosion increase the kinetic energy of a system?
Reasoning: Chemical or internal energy may transform into kinetic energy.
34 / 35
Which situation demonstrates momentum conservation but kinetic energy increase?
Reasoning: Internal energy can increase kinetic energy while momentum remains conserved.
35 / 35
In a closed system, momentum conservation results from:
Reasoning: No external force means no change in total momentum.
Your score is
Restart quiz
