601_multiple_choice_2010

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1. A ball of mass m is thrown vertically upwards. Air resistance is not negligible. Assume the force of air resistance has magnitude proportional to the velocity, and direction opposite to the velocity's. At the highest point, the ball's acceleration is: (A) 0 (B) less than g (C) g (D) greater than g

(C) t = 7.5 s (D) t = 12 s

2. Air track car A has mass m and velocity v. Air track car B has mass 2m and velocity 3v . The same constant force F is applied to each car until it stops. Car A is brought to rest in time t. The time required to stop car B is: (A) 2t (B) 3t (C) 6t (D) 9t

6. The accompanying figure is a graph of an object’s position as a function of time. Which teetere segment corresponds to a time when the object has a negative acceleration? (A) A (B) B (C) C (D) D

3. A hypothetical planet has density p, radius R, and surface gravitational acceleration g. If the radius of the planet was doubled, but the planetary density stayed the same, the acceleration due to gravity at the planet's surface would be:

7. The driver of a 1000 kg car tries to turn through a circle of radius 100 m on an unbanked curve at a speed of 10 m/s. The maximum frictional force between the tires and the slippery road is 900 N. The car will: (A) Slide into the inside of the curve. (B) Make the turn. (C) Slow down due to the centrifugal force. (D) Slide off to the outside of the curve.

(A) (B) (C) (D)

4g 2g g g/2

4. A motorist travels 320 km at 80 km/h and then 320 km at 100 km/h. What is the average speed of the motorist for the entire trip? (A) 84 km/h (B) 89 km/h (C) 90 km/h (D) 91 km/h 5. A sports car is stopped at a light. At t = 0 the light changes and the sports car accelerates at a constant 2.0 m/s2. At t = (10/3) s a station wagon traveling at a constant 15 m/s in the same direction passes the stop light. When does the station wagon catch up to the sports car? (A) Never (B) t = 5.0 s

8. A ball of mass m is fastened to a string. The ball swings in a vertical circle of radius R with the other end of the string held fixed. Neglecting air resistance, the difference between the string’s tension at the bottom of the circle and the top. (A) mg (B) 2mg (C) 4mg (D) 6mg 9. The gravitational acceleration on the surface of the moon is 1.6 m/s2. The radius of the moon is 1.7 x 106 m. The period of a satellite placed in a low circular orbit about the moon is most nearly (A) 1.0 x 103 s (B) 6.5 x 103 s


(C) 1.1 x 106 s (D) 5.0 x 106 s 10. A mass of 1kg is whirled in a vertical circle of radius R. If the minimum tension in the sting is 8N the maximum tension is. (A) 27N (B) 28N (C) 27.81 N (D) 27.72 N 11. A corner is designed for a maximum speed of 25ms‐1. If the turning radius of the corner is 25m, what is the angle at which corner should be banked at. (A) 600 (B) 68.50 (C) 65.50 (D) 670 12. The force exerted by a fluid on a submerged object at any point is (A) Along the surface of the object (B) Away from the surface of the object (C) Perpendicular to the surface of the object (D) Parallel to the surface of the object 13. It is known that the pressure P at a depth h below the surface of a liquid open to the atmosphere is greater than atmosphere pressure by the amount (A) Po (B) ρgh (C) P0 ‐ρgh (D) P0 + ρgh 14. How is the work done (W1) on lifting a mass by a vacuum cleaner related to the work done (W2) by the pump in the vacuum cleaner. (A) W1 = W2 (B) W2 > W1 (C) W1 > W2 (D) W1 = ‐W2 15. A roller coaster is moving around a circular loop of radius R. The speed of the car at the top and the circular loop is given by

(A) (B) (C) (D)

2√gR √2Rg √Rg √Rg/2

16. A bob of mass m is whirled in a vertical circle of radius R. The tension in the string at the top of the motion is given by (A) T = mg (B) T = mv2 + mg (C) T= mv2/R + mg (D) T= mv2/R – mg 17. A mass connected to a string going in a vertical circle breaks free. In which direction would the mass move in (A) radially outwards (B) in the direction of the acceleration (C) in the direction of the velocity (D) in the direction of the displacement 18. The centripetal acceleration of a body is ½ a and its velocity is v1. If the radius r of the circle is doubled, what is the new value of the velocity v2 of the body given that the acceleration is halved. (A) v2 = v1 (B) v2 > v1 (C) v2 < v1 (D) 0 19. A car is moving round a banked track in a circular path. If the only force at wheels are the reaction force R1 and R2 respectively. What is the value of the force towards the centre of the track given as (A) R1 + R2 (B) (R1 – R2 ) Sin θ (C) (R1 / R2 ) Sin θ (D) (R1 + R2 ) Sin θ 20. Objects that are either at rest or not moving with constant velocity are said to be in equilibrium, because (A) the mass is too large (B) the resultant force adding is greater zero (C) the parallel forces acting on it is not equal


(D) the vector sum of all the forces acting on the object is zero 21. If a concrete block is balanced with a centre of mass vertically above the supporting edge. The torque above the supporting edge is zero due to (A) the mass of the domino (B) the resultant force on the domino is zero (C) the gravitation force on the domino is zero (D) the line of action through the dominion is parallel to the centre of mass. 22. A plank of AB mass M of a length L/2 a is in equilibrium when hanged from a point, which is L/5 can from A. What is the value of the force that must be placed at A for equilibrium (A) 4M (B) 5/2 M (C) 2/5 M (D) M 23. A metal rod of AB length L and weight W is suspended by two metal cables. One cable is L/3 from B, while the other is at A what is the force in the cable at A? (A) W (B) W/2 (C) ¾ W (D) ¼ W 24. A monkey of mass 20kg rides on a 40 kg trolley moving with a speed of 8 m s‐1 along a flat surface. The monkey jumps vertically to grab the overhanging branch of a tree. At what speed will the trolley move off? (A) (B) (C) (D)

12 m s‐1 8 m s‐1 5 m s ‐1 m s‐1

25. An object of mass M travelling with a velocity u collides with a stationary object of mass 2M. After the collision the two masses stick together and move with a common velocity v. The magnitude of v is equal to (A) 3u (B) u (C) u/2

(D) u/3 26. Two rocks are spun around in circular paths at ends of strings of equal length. What quantity MUST be the same for both rocks if the tension in the strings is equal? (A) (B) (C) (D)

speed acceleration mass kinetic energy

27. Aeroplane A is travelling at twice the speed of Aeroplane B. Plane A is half the mass of Aeroplane B. Which of the following statements is correct?

(A) The two aeroplanes have the same kinetic energy (B) Aeroplane A has twice the kinetic energy of plane B (C) Aeroplane A has half the kinetic energy of plane B (D) Aeroplane A has one quarter of the kinetic energy of plane B 28. An object is rotated in a vertical circle with a constant angular velocity. Which of the following quantities remain constant as the object moves round its circle I. The tension in the string II. The acceleration of the object. III. The kinetic energy of the object (A) (B) (C) (D)

30

I and II only II and III only I and III only I, II and III

Which of the following experimental techniques reduces the systematic error of the quantity being investigated? (A) (B) (C) (D)

Measuring the diameter of a steel rod several times and finding an average. Timing a large number of oscillations of a simple pendulum to find a period. Plotting a series of voltage and current readings for an ohmic device on a graph and using its gradient to find resistance. Adjusting a voltmeter to remove its zero error before measuring a


31 32 33 34 35

potential difference Marcia needs to find the mass of her dog but he will not stay on the bathroom scale. So first she weighs herself, getting 47 1kg. Then she stands on the balance holding her dog and the reading becomes 64 1kg. From these readings the percentage error (or uncertainty) in the mass of the dog is (A) (B) (C) (D)

1% 2% 6% 12%

Two velocity vectors of magnitude 20km h‐1 and 40 km h‐1 are to be subtracted. Which of the following is NOT a possible value for the answer? (A) (B) (C) (D)

10 km h‐1 20 km h‐1 30 km h‐1 40 km h‐1

An object of mass, m, is moving with kinetic energy E. which of the following has the same base units as it momentum? (A) (B) (C) (D)

√ mE mE2

A tennis ball is given a horizontal velocity of 8 m s‐1 when it is hit at a height of 1.8 m above the ground. It is in the air for (A) (B) (C) (D)

0.37 s 0.61 s 2.95 s 8.89 s

An object of mass M travelling with a velocity u collides with a stationary object of mass 2M. after collision the two masses stick together and move with a common velocity v. the magnitude of v is equal to (A) (B) (C) (D)

3u u ⁄2 ⁄3

36.

An object moving at constant speed in a circle of radius r turns through an angle θ (measured in radians) in a time t. the velocity v along a tangent is given by (A)

v = 2 rθ/t

(B)

v =

(C)

v =

37.

(D)

v =

Which of the following equations represents the gravitational field strength of a point a distance h from the surface of the Earth where r is the radius of the Earth?

(A)

g’ =

g

(B)

g’ =

g

(C)

g’ = g

(D)

g’ =

38. 39.

g

A hot air balloon moving upwards has a total weight of 200N and a volume of 20 m3. Assuming the density of the air outside the balloon is 1.2 kg m‐3, the NET upward force on the balloon is then approximately (A) (B) (C) (D)

24N 40N 176N 240N

A hammer thrower makes 4 complete revolutions in 3.2 s. The distance between the hammer and the thrower is 1.5 m. What is the centripetal acceleration of the hammer? (A) (B) (C) (D)

0.375 m s‐2 2.9 m s‐2 5.8 m s‐2 92.5 m s‐2

40.

A bee is pushed by a wind of constant force from rest for a fixed distance. The kinetic energy acquired by the bee of mass, m is (A) (B) (C)

proportional to √ proportional to m proportional to


41. 42. 43.

(D)

independent of m

A car travelling at a constant velocity is provided with 15kW of useful power. The driving force on the car 600N. What is the velocity of the car? (A) (B) (C) (D)

2 m s‐1 5 m s‐1 10 m s‐1 25 m s‐1

In a simple harmonic motion with amplitude A and period T, the maximum velocity is (A) (B) (C) (D)

A/T A/2 T 2 /AT 2 A/T

A mass of 250g hanging at the end of a spring of spring constant, k, makes 21 oscillations in 11 seconds. What would be the period if the system were taken to a planet where gravity was ¼ of that on Earth? (A)

s

(B)

(C)

44.

(D)

45.

s s

4

s

A child’s swing of mass 10kg is oscillating with simple harmonic motion where the maximum height reached is 0.5m above the equilibrium position. The following table shows pairs of energy values during the oscillation. Which pair is NOT possible? PE/J KE/J (A) 0 49 (B) 18 31 (C) 38 13 (D) 49 0 The refractive index of water is 1.33. What will be the speed of light in water? (A) (B) (C) (D)

3.0 × 10 m s‐1 2.26 × 10 m s‐1 4.0 × 10 m s‐1 1.33 × 10 m s‐1


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