Q. A mass is measured as 5.0 kg with an uncertainty of ±0.1 kg. If this mass is used to calculate weight (W = mg), what is the uncertainty in weight if g = 9.8 m/s²?
A.±0.2 N
B.±0.5 N
C.±0.1 N
D.±0.4 N
Solution
Uncertainty in weight = g * (uncertainty in mass) = 9.8 * 0.1 = ±0.98 N, rounded to ±1 N.
Q. A mass m is attached to a spring of spring constant k. If the mass is displaced from its equilibrium position and released, what is the time period of the oscillation?
A.2π√(m/k)
B.2π√(k/m)
C.π√(m/k)
D.π√(k/m)
Solution
The time period T of a mass-spring system in simple harmonic motion is given by T = 2π√(m/k).
Q. A mass m is attached to a spring of spring constant k. If the mass is displaced by a distance x from its equilibrium position, what is the restoring force acting on the mass?
A.kx
B.-kx
C.mg
D.-mg
Solution
The restoring force in simple harmonic motion is given by Hooke's law, which states that the force is proportional to the displacement and acts in the opposite direction. Therefore, the restoring force is -kx.
Q. A mass m is attached to a string and is whirled in a horizontal circle. If the radius of the circle is halved, what happens to the tension in the string if the speed remains constant?
A.It doubles
B.It remains the same
C.It halves
D.It quadruples
Solution
Tension T = mv²/r. If r is halved, T doubles for constant speed.
Q. A mass m is attached to a string and is whirled in a vertical circle. At the highest point of the circle, what is the minimum speed required to keep the mass in circular motion?
A.√(g*r)
B.g*r
C.2g*r
D.g/2
Solution
At the highest point, the centripetal force is provided by the weight. Minimum speed = √(g*r).
Q. A mass m is attached to a string and is whirled in a vertical circle. At the highest point of the circle, the tension in the string is T. What is the expression for T?
A.T = mg
B.T = mg - mv²/r
C.T = mg + mv²/r
D.T = mv²/r
Solution
At the highest point, T + mg = mv²/r, thus T = mg - mv²/r.
Q. A mass m is attached to a string and is whirled in a vertical circle. At the highest point of the circle, what is the condition for the mass to just complete the circular motion?
A.Tension = 0
B.Tension = mg
C.Tension = 2mg
D.Tension = mg/2
Solution
At the highest point, the centripetal force is provided by the weight of the mass, so T + mg = mv²/r. For T = 0, mg = mv²/r.
Q. A mass m is attached to a string and is whirled in a vertical circle. At the top of the circle, the tension in the string is T. What is the expression for the tension at the bottom of the circle?
Q. A mass m is attached to a string of length L and is swung in a vertical circle. At the highest point of the circle, what is the minimum speed required to keep the mass in circular motion?
A.√(gL)
B.√(2gL)
C.gL
D.2gL
Solution
At the highest point, the centripetal force must equal the weight: mv²/L = mg, thus v = √(gL).
Q. A mass-spring system is subjected to a periodic force. If the amplitude of oscillation is 0.1 m and the frequency is 2 Hz, what is the maximum velocity of the mass?
Q. A mass-spring system is subjected to a periodic force. If the amplitude of the forced oscillation is 0.1 m and the damping coefficient is 0.2 kg/s, what is the maximum velocity of the oscillation?
A.0.1 m/s
B.0.2 m/s
C.0.3 m/s
D.0.4 m/s
Solution
Maximum velocity (v_max) = Aω, where ω = 2πf. Assuming f = 1 Hz, v_max = 0.1 * 2π * 1 = 0.2 m/s.
Q. A mass-spring system oscillates with a frequency of 2 Hz. If the system is damped, what is the relationship between the damped frequency and the natural frequency?
A.Damped frequency is greater
B.Damped frequency is equal
C.Damped frequency is less
D.Damped frequency is unpredictable
Solution
In a damped system, the damped frequency is always less than the natural frequency.
Q. A mass-spring system oscillates with a natural frequency of 3 Hz. If a damping force is applied, what is the new frequency of oscillation if the damping ratio is 0.1?
A.2.8 Hz
B.2.9 Hz
C.3.0 Hz
D.3.1 Hz
Solution
New frequency (ω_d) = ω_n√(1-ζ²) = 3√(1-0.1²) ≈ 2.9 Hz.