EXAM 1 A PHYS 102 SUMMER 2003

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The exam is closed book and closed notes.

Make sure you put your name on the SCANTRON form.

Here are some useful equations:

Vectors: Ax = A cos; Ay = A sin; A =;  = tan-1;

R = A + B  Rx = Ax+ Bx , Ry = Ay + By

One-dimensional motion: x = vot +at2 v = vo + at 2ax = v2 - v02

Free-fall: y = vo t - gt2 v = vo - gt,

Projectile motion: x = voxt y = v0yt - gt2 vy = voy - gt vox = vocos voy = vosin xmax = R = xmax = voxttot

Fnet = ma, Fg = mg , Incline: Fgx = mgsin, Fgy = mgcos

SAMPLE EXAM 1 PHYS 102 SUMMER SESSION

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1. A vector A in the x,y plane has an x component of 24 and an y component of 24. The direction (angle the vector A makes with the positive x axis) of this vector is closest to:

A) 26°

B) 30°

C) 45°

D) 127°

E) 210°

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2. A woman walks 180 m in the direction 650 north of east, then 80 m directly east. Find the magnitude of the displacement vector A + B.

A) 100 m

B) 146 m

C) 226 m

D) 440 m

E) 558 m

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3. A particle moves along a straight path with a velocity v that varies with time t as shown in the graph. How far from its initial position at t = 0 will the particle be when t = 6 seconds?

A) 6 m

B) 12 m

C) 18 m

D) 36 m

E) 44 m

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4. A car moving initially at 12 m/s, travels 180 m in 6 s along a straight line with constant acceleration. The acceleration of the car is:

A) 0. 0 m/s2

B) 0..5 m/s2

C) 1..5 m/s2

D) 3. 0 m/s2

E) 6. 0 m/s2

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5. If a car traveling at 60 km/h suddenly locks its brakes and skids 80 m, how long will it take for the car to come to a complete stop?

A) 1.2 s

B) 2.4 s

C) 4.8 s

D) 9.6 s

E) 15.4 s

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6. A stone is thrown vertically upward with an initial speed of 16 m/s. Its position 2 seconds later is:

A) 12.4 m

B) 26.2 m

C) 32.4 m

D) 38.5 m

E) 46.0 m

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7. A 60 kg ball is dropped from a height of 48 m above a table. What is the velocity of the ball just before impact?

A) 11 m/s

B) 15 m/s

C) 22 m/s

D) 31 m/s

E) 45 m/s

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A projectile is fired over level ground with an initial velocity 50 m/s at an angle 350 above the horizontal.

8. The horizontal and vertical components of its velocity 4 seconds later are closest to:

A) vx = 41 m/s, vy = 9 m/s

B) vx = 25 m/s, vy = 18 m/s

C) vx = 41 m/s, vy = -10.5 m/s

D) vx = 25 m/s, vy = -8 m/s

E) vx = 41 m/s, vy = 21 m/s

9. What is the maximum height reached by the projectile?

A) 6 m

B) 12 m

C) 18 m

D) 36 m

E) 42 m

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10. A ball thrown horizontally from a point 8 m above the ground, strikes the ground after traveling horizontally a distance of 18 m With what speed was it thrown?

A) 2.0 m/s

B) 7.0 m/s

C) 8.0 m/s

D) 11.0 m/s

E) 14.0 m/s

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11. In the absence of all forces, a moving object will

A) slow down and eventually stop.

B) move at constant velocity.

C) immediately come to rest.

D) accelerate.

E) none of the above.

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12. A 6-kg suitcase is placed on a scale that is in an elevator moving with upward

acceleration of 2.0 m/s2. What does the scale read?

A) 57 N

B) 71 N

C) 86 N

D) 91 N

E) none of the above

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13. Starting from rest, a 8-kg body reaches a speed of 6 m/s in a distance of 4 m. What is the net force acting on the body?

A) 16 N

B) 28 N

C) 36 N

D) 65 N

E) 98 N

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A 38-kg crate is pulled along a horizontal, frictionless floor

by a cord that exerts a 180-N tension force at an angle  = 300 as shown .

14. The acceleration of the block is closest to

A) 1.8 m/s2

B) 2. 4 m/s2

C) 3.6 m/s2

D) 4.1 m/s2

E) 8.5 m/s2

15. The normal force on the block is closest to

A) 110 N

B) 146 N

C) 185 N

D) 211 N

E) 282 N

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16. Block B, which has a mass of 100 kg, is raised from the Earth's surface by means of pulley system shown. If the tension F in the string has a magnitude of 1200 N, what is the acceleration of the block B ?

A) 12 m/s2

B) 8 m/s2

C) 6 m/s2

D) 4 m/s2

E) 2 m/s2

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17. A 10-kg block on a frictionless, horizontal plane is pulled by a cord over a massless, frictionless pulley . What tension force T is needed so that the 10-kg block can move at acceleration of 2.8 m/s2 ?

A) 12 N

B) 28 N

C) 42 N

D) 65 N

E) 98 N

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18. A 5-kg box sitting on a horizontal surface is pulled by a 15-N force. A 5-N friction force retards the motion. The acceleration of the object is closest to

A) 2.0 m/s2

B) 3.0 m/s2

C) 4.0 m/s2

D) 5.0 m/s2

E) 6.0 m/s2

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A 2-kg block, initially at rest, slides down a frictionless inclined plane. Angle of incline is

350, and incline is 0.8 m long.

19. The normal force on the block is closest to

A) 11 N

B) 16 N

C) 25 N

D) 31 N

E) 43 N

20. Find the speed of the block at the bottom of the incline.

A) 1.80 m/s

B) 3.00 m/s

C) 5.60 m/s

D) 7.20 m/s

E) 8.50 m/s

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