Name: __________________________ت
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1. |
A 6-kg block sitting on a smooth table is connected to a free-hanging 2-kg mass by a stretchless, massless cord that passes over a small frictionless pulley. The acceleration of the two-block system is |
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A) |
equal to g. |
D) |
one-fourth of g. |
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B) |
half of g. |
E) |
two-thirds of g. |
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C) |
one-third of g. |
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2. |
You are riding an elevator that is accelerating upward at 2.20 m/s2.ت You have a spring balance accurately calibrated in newtons.ت When you hang a mass of 10.0 kg on the balance, the reading of the balance is |
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A)ت 120 Nتتت B)ت 981 Nتتت C)ت 76.0 Nتتت D)ت 10.0 Nتتت E)ت 9.81 N |
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3. |
Three forces F1, F2 and F3 act on an object. If F1 = 3N i + 5N j + 7N k, F2 = ِ5N i ِ 2N j ِ2N k, and the object is moving at constant velocity then the vector force F3 is |
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A) |
ِ2N i ِ 3N j ِ 5N k |
D) |
ِ8N i ِ 7N j ِ 9N k |
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B) |
2N i ِ 3N j ِ 5N k |
E) |
8N i + 7 N j +9N k |
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C) |
2N i + 3N j ِ 5N k |
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4. |
Your heart pumps 80 g of blood with each beat.ت The blood starts from rest and reaches a speed of 0.60 m/s in the aorta.ت If each beat takes 0.16 s, the average force exerted on the blood is |
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A)ت 3.0 « 102 Nتتت B)ت 0.22 Nتتت C)ت 0.16 Nتتت D)ت 0.30 Nتتت E)ت 0.98 N |
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5. |
A car experiences both a centripetal and a tangential acceleration.ت For which of the following would this be true? |
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A) |
It is going around a curve at a constant speed. |
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B) |
It is going around a curve and slowing down. |
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C) |
It is going along a straight road at a constant speed. |
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D) |
It is going along a straight road and increasing its speed. |
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E) |
It is going along a straight road and decreasing its speed. |
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6. |
The kinetic energy of a car is 1.00 « 105 J.ت If the car's speed is increased by 20 percent, the kinetic energy of the car becomes |
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A) |
4.00 « 103 J |
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B) |
1.20 « 105 J |
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C) |
1.44 « 105 J |
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D) |
1.04 « 105 J |
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E) |
unknown; the answer depends on the mass of the car, which is not given |
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7. |
A constant force of 45 N directed at angle q to the horizontal pulls a crate of weight 100 N from one end of a room to another a distance of 4 m. Given that the vertical component of the pulling force is 12 N, calculate the work done by the force in moving the crate. |
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A)ت 4.1 « 102 Jتتت B)ت 48.0 Jتتت C)ت 3.9 « 102 N/mتتت D)ت 1.7 « 102 Jتتت E)ت 3.9 « 103 J |
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8. |
What is the power output needed from a motor to lift, in the absence of friction, a mass of 1.5 « 104 kg 25 m in 6.0 s at constant speed? |
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A) 2.0 « 106 W B) 6.1 « 105 W C)2.2 « 104 W D) 8.3 « 105 W E)ت 3.1 « 105 W |
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9. |
A projectile of mass 1.02 kg is propelled from ground level with kinetic energy of 450 J.ت At the exact top of its trajectory, its kinetic energy is 250 J.ت To what height above the starting point does the projectile rise? |
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A) 45 mتتت B) 25 mتتت C) 70 mتتت D) 20 mتتت E) 35 m |
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10. |
A 10-kg box is at the top of a plane, of length 5 m, inclined at 37¼ with the horizontal.ت The box starts from rest and slides down the plane.ت The coefficient of kinetic friction is 0.20.ت The magnitude of the change in the potential energy of the box is |
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A)ت 30 kJتتت B)ت 0.10 kJتتت C)ت 0.29 kJتتت D)ت 0.46 kJتتت E)ت 0.39 kJ |
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11. |
A simple pendulum has a
bob of mass M=2kg. The bob
is on a light string of length |
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A) |
What is the potential energy at A? |
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B) |
What is the speed of the bob at B? |
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C) |
What is the centripetal force in the string when the bob is at B? |
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D) |
What is the tension in the string when the bob is at B? |
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= 4.9m. The
string is fixed at C.ت