Q. In terms of stability, what is the effect of lowering the center of mass of a rolling object?
A.
Increases stability
B.
Decreases stability
C.
No effect on stability
D.
Depends on the object's shape
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Solution
Lowering the center of mass of a rolling object increases its stability, making it less likely to tip over.
Correct Answer:
A
— Increases stability
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Q. In the kinetic theory of gases, which of the following assumptions is NOT true?
A.
Gas molecules are in constant random motion
B.
Gas molecules occupy a negligible volume
C.
Gas molecules experience no intermolecular forces
D.
Gas molecules have significant mass
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Solution
In the kinetic theory of gases, it is assumed that gas molecules occupy a negligible volume and have negligible mass compared to the volume they occupy.
Correct Answer:
D
— Gas molecules have significant mass
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Q. In the kinetic theory, what is assumed about the collisions between gas molecules?
A.
They are perfectly elastic
B.
They are perfectly inelastic
C.
They lose energy
D.
They are not considered
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Solution
In the kinetic theory of gases, it is assumed that collisions between gas molecules are perfectly elastic, meaning they conserve kinetic energy.
Correct Answer:
A
— They are perfectly elastic
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Q. Two cars are moving towards each other, one at 50 km/h and the other at 70 km/h. What is the speed of one car relative to the other?
A.
20 km/h
B.
120 km/h
C.
50 km/h
D.
70 km/h
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Solution
The speed of one car relative to the other is the sum of their speeds since they are moving towards each other: 50 km/h + 70 km/h = 120 km/h.
Correct Answer:
B
— 120 km/h
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Q. Two trains are moving towards each other on parallel tracks. Train A is moving at 90 km/h and Train B at 70 km/h. What is the speed of Train B relative to Train A?
A.
20 km/h
B.
70 km/h
C.
90 km/h
D.
160 km/h
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Solution
The speed of Train B relative to Train A is the sum of their speeds: 90 km/h + 70 km/h = 160 km/h.
Correct Answer:
D
— 160 km/h
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Q. What does the term 'mean free path' refer to in the context of gases?
A.
The average distance traveled by a molecule between collisions
B.
The average speed of gas molecules
C.
The average time between collisions
D.
The average kinetic energy of gas molecules
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Solution
The mean free path is defined as the average distance a molecule travels before colliding with another molecule.
Correct Answer:
A
— The average distance traveled by a molecule between collisions
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Q. What happens to the acceleration of an object if the mass is doubled while the force remains constant?
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
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Solution
According to Newton's second law, if mass is doubled and force remains constant, acceleration will halve (a = F/m).
Correct Answer:
B
— It halves
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Q. What happens to the angular momentum of a rigid body if no external torque acts on it?
A.
It increases
B.
It decreases
C.
It remains constant
D.
It becomes zero
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Solution
According to the law of conservation of angular momentum, if no external torque acts on a rigid body, its angular momentum remains constant.
Correct Answer:
C
— It remains constant
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Q. What happens to the gravitational force if one of the masses is tripled?
A.
It triples
B.
It remains the same
C.
It doubles
D.
It increases by a factor of nine
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Solution
If one of the masses is tripled, the gravitational force also triples, as F is directly proportional to the product of the masses.
Correct Answer:
A
— It triples
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Q. What happens to the induced current if the magnetic field is removed?
A.
It increases
B.
It decreases
C.
It reverses direction
D.
It stops
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Solution
If the magnetic field is removed, the induced current stops because there is no longer a change in magnetic flux.
Correct Answer:
D
— It stops
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Q. What happens to the speed of light when it passes from air into water?
A.
It increases
B.
It decreases
C.
It remains the same
D.
It becomes zero
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Solution
The speed of light decreases when it passes from air into water due to the higher refractive index of water.
Correct Answer:
B
— It decreases
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Q. What happens to the total mechanical energy of a rolling object if it rolls without slipping?
A.
It increases
B.
It decreases
C.
It remains constant
D.
It depends on the surface
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Solution
In rolling without slipping, the total mechanical energy (potential + kinetic) remains constant due to conservation of energy.
Correct Answer:
C
— It remains constant
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Q. What is the acceleration of a 3 kg object subjected to a net force of 12 N?
A.
2 m/s²
B.
3 m/s²
C.
4 m/s²
D.
5 m/s²
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Solution
Using F = ma, a = F/m = 12 N / 3 kg = 4 m/s².
Correct Answer:
C
— 4 m/s²
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Q. What is the acceleration of an object in simple harmonic motion at maximum displacement?
A.
Zero
B.
Maximum
C.
Minimum
D.
Constant
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Solution
The acceleration is maximum at maximum displacement, directed towards the equilibrium position.
Correct Answer:
B
— Maximum
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Q. What is the angular displacement of a wheel that rotates from rest to an angular velocity of 10 rad/s in 5 seconds with a constant angular acceleration?
A.
25 rad
B.
50 rad
C.
75 rad
D.
100 rad
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Solution
Using the formula θ = ω₀t + 0.5αt², where ω₀ = 0, α = 2 rad/s², and t = 5 s, we find θ = 0 + 0.5 * 2 * 5² = 25 rad.
Correct Answer:
B
— 50 rad
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Q. What is the angular displacement of an object that rotates through an angle of 90 degrees?
A.
0.5 radians
B.
1 radian
C.
1.57 radians
D.
1.5 radians
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Solution
90 degrees is equal to π/2 radians, which is approximately 1.57 radians.
Correct Answer:
A
— 0.5 radians
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Q. What is the angular momentum of a 2 kg object moving in a circle of radius 3 m at a speed of 4 m/s?
A.
24 kg·m²/s
B.
12 kg·m²/s
C.
6 kg·m²/s
D.
8 kg·m²/s
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Solution
Angular momentum L = mvr = 2 kg × 4 m/s × 3 m = 24 kg·m²/s.
Correct Answer:
A
— 24 kg·m²/s
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Q. What is the center of mass of a system of particles?
A.
The point where the total mass is concentrated
B.
The average position of all particles
C.
The point of maximum gravitational force
D.
The point where all forces balance
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Solution
The center of mass of a system of particles is defined as the average position of all the particles in the system, weighted by their masses.
Correct Answer:
B
— The average position of all particles
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Q. What is the centripetal acceleration of a car moving in a circular path of radius 50 m at a speed of 20 m/s?
A.
4 m/s²
B.
8 m/s²
C.
10 m/s²
D.
16 m/s²
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Solution
Centripetal acceleration is given by a_c = v²/r = (20 m/s)² / 50 m = 8 m/s².
Correct Answer:
B
— 8 m/s²
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Q. What is the centripetal acceleration of an object moving in a circle of radius 3 m at an angular velocity of 4 rad/s?
A.
4 m/s²
B.
12 m/s²
C.
16 m/s²
D.
24 m/s²
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Solution
Centripetal acceleration a_c = rω² = 3 m * (4 rad/s)² = 3 * 16 = 48 m/s².
Correct Answer:
B
— 12 m/s²
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Q. What is the centripetal force required to keep a 2 kg object moving in a circle of radius 3 m at a speed of 4 m/s?
A.
10.67 N
B.
8 N
C.
6 N
D.
12 N
Show solution
Solution
Centripetal force F = mv²/r = 2 kg * (4 m/s)² / 3 m = 10.67 N.
Correct Answer:
A
— 10.67 N
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Q. What is the condition for a rolling object to be in pure rolling motion?
A.
The object must not slide at all.
B.
The object must have a constant velocity.
C.
The object must have a constant acceleration.
D.
The object must be on a flat surface.
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Solution
Pure rolling motion occurs when the point of contact between the rolling object and the surface is at rest relative to the surface, meaning there is no sliding.
Correct Answer:
A
— The object must not slide at all.
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Q. What is the critical angle for total internal reflection?
A.
sin(θc) = n2/n1
B.
sin(θc) = n1/n2
C.
θc = n1/n2
D.
θc = n2/n1
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Solution
The critical angle θc can be calculated using sin(θc) = n2/n1, where n1 is the refractive index of the medium where the light is coming from.
Correct Answer:
A
— sin(θc) = n2/n1
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Q. What is the effect of friction on the motion of an object according to Newton's laws?
A.
It increases acceleration
B.
It decreases acceleration
C.
It has no effect
D.
It reverses direction
Show solution
Solution
Friction opposes the motion of an object, thus decreasing its acceleration according to Newton's laws.
Correct Answer:
B
— It decreases acceleration
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Q. What is the effect of increasing the area of a loop in a uniform magnetic field on the induced emf?
A.
Induced emf increases
B.
Induced emf decreases
C.
Induced emf remains the same
D.
Induced emf becomes zero
Show solution
Solution
The induced emf depends on the rate of change of magnetic flux, not directly on the area of the loop in a uniform magnetic field. Therefore, it remains the same if the magnetic field is constant.
Correct Answer:
C
— Induced emf remains the same
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Q. What is the effect of increasing the distance between two masses on the gravitational force?
A.
The gravitational force increases.
B.
The gravitational force decreases.
C.
The gravitational force remains the same.
D.
The gravitational force becomes zero.
Show solution
Solution
According to the inverse square law, increasing the distance between two masses decreases the gravitational force between them.
Correct Answer:
B
— The gravitational force decreases.
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Q. What is the effect of increasing the radius of a rolling object on its moment of inertia?
A.
It decreases the moment of inertia.
B.
It increases the moment of inertia.
C.
It has no effect on the moment of inertia.
D.
It depends on the mass of the object.
Show solution
Solution
The moment of inertia increases with the square of the radius, as seen in the formula I = k m r^2, where k is a constant depending on the shape.
Correct Answer:
B
— It increases the moment of inertia.
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Q. What is the effect of increasing the temperature of a gas on its average molecular speed?
A.
Average speed decreases
B.
Average speed remains the same
C.
Average speed increases
D.
Average speed becomes zero
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Solution
Increasing the temperature of a gas increases the average kinetic energy of its molecules, which in turn increases their average speed.
Correct Answer:
C
— Average speed increases
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Q. What is the effect of increasing the temperature on the speed of sound in air?
A.
It decreases
B.
It increases
C.
It remains the same
D.
It becomes zero
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Solution
The speed of sound in air increases with an increase in temperature.
Correct Answer:
B
— It increases
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Q. What is the force required to keep a 10 kg object moving at a constant velocity on a frictionless surface?
A.
0 N
B.
10 N
C.
100 N
D.
1 N
Show solution
Solution
On a frictionless surface, no net force is required to maintain constant velocity, so the force is 0 N.
Correct Answer:
A
— 0 N
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