PHY101 Midterm Past Paper 2009

MIDTERM EXAMINATION · Spring 2009 · PHY101- Physics (Session - 2)

Q1. The lowest tone produced by a certain organ comes from a 3.0-m pipe with both ends open. If the speed of sound is 340m/s, the frequency of this tone is approximately:

1. A. 7Hz
2. B. 14 Hz
3. C. 28 Hz
4. D. 57 Hz

Correct answer: D. 57 Hz

Q2. 1. To raise the pitch of a certain piano string, the piano tuner:

1. A. loosens the string
2. B. tightens the string
3. C. shortens the string
4. D. lengthens the string

Correct answer: A. loosens the string

Q3. A force of 5000N is applied outwardly to each end of a 5.0-m long rod with a radius of 34.0 cm and a Young's modulus of 125 × 108N/m2. The elongation of the rod is:

1. 0.0020mm
2. 0.0040mm
3. 0.14mm
4. 0.55mm

Correct answer: 0.55mm

Q4. A particle oscillating in simple harmonic motion is:

1. never in equilibrium because it is in motion
2. never in equilibrium because there is always a force
3. in equilibrium at the ends of its path because its velocity is zero there
4. in equilibrium at the center of its path because the acceleration is zero there

Correct answer: in equilibrium at the center of its path because the acceleration is zero there

Q5. ( M a r k s: 1 ) - Please choose vuzs one

In simple harmonic motion, the restoring force must be proportional to the:

1. amplitude
2. frequency
3. velocity
4. displacement

Correct answer: displacement

Q6. A 160-N child sits on a light swing and is pulled back and held with a horizontal force of 100 N. The magnitude of the tension force of each of the two supporting ropes is:

1. 60N
2. 94N
3. 120N
4. 190N

Correct answer: 94N

Q7. ( M a r k s: 1 ) - Please choosevu zsone

An object attached to one end of a spring makes 20 vibrations in 10 s. Its angular frequency is:

1. 12.6 rad/s
2. 1.57 rad/s
3. 2.0 rad/s
4. 6.3 rad/s

Correct answer: 12.6 rad/s

Q8. For an object in equilibrium the net torque acting on it vanishes only if each torque is calculated about:

1. the center of mass
2. the center of gravity
3. the geometrical center
4. the same point

Correct answer: the same point

Q9. Ten seconds after an electric fan is turned on, the fan rotates at 300 rev/min. Its average angular acceleration is:

1. 3.14 rad/s2
2. 30 rad/s2
3. 30 rev/s2
4. 50 rev/min2
5. 1800 rev/s2

Correct answer: 3.14 rad/s2

Q10. A 4.0-N puck is traveling at 3.0m/s. It strikes a 8.0-N puck, which is stationary. The two pucks stick together. Their common final speed is:

1. 1.0m/s
2. 1.5m/s
3. 2.0m/s
4. 2.3m/s

Correct answer: 1.0m/s

Q11. An object moving in a circle at constant speed:

1. must have only one force acting on it
2. is not accelerating
3. is held to its path by centrifugal force
4. has an acceleration of constant magnitude

Correct answer: has an acceleration of constant magnitude

Q12. A plane traveling north at 200m/s turns and then travels south at 200m/s. The change in its velocity is:

1. 400m/s north
2. 400m/s south
3. zero
4. 200m/s south

Correct answer: 400m/s south

Q13. At time t = 0 a car has a velocity of 16 m/s. It slows down with an acceleration given by −0.50t, in m/s2 for t in seconds. It stops at t =

1. 64 s
2. 32 s
3. 16 s
4. 8.0 s

Correct answer: 8.0 s

Q14. 1 mi is equivalent to 1609 m so 55 mph is:

1. 15 m/s
2. 25 m/s
3. 66 m/s
4. 88 m/s

Correct answer: 25 m/s

Q15. If you walk along the top of a fence, why does holding your arms out help you to keep your balance?

because the arms keeps the movement of weight of body easy