EXAM 1 PHYS 102

The exam is closed book and closed notes.

Here are some useful equations:

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

R = A + B Rx = Ax+ Bx , Ry = Ay + By R =; g = 9.8 m/s2

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

Asphere = 4πR2 Vsphere = (4/3) πR3 Vcyl = πR2h 1 km = 1000 m 1 h = 3600 s 1 inch = 2.54 cm 1 mi = 1609 m

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1. A train travels at constant speed of 32 m/s. The speed in miles per hour is closest to:

A) 90 mi/h

B) 70 mi/h

C) 50 mi/h

D) 40 mi/h

E) 30 mi/h

2. A drinking glass has a radius of 1.25 inches and is 5.5 inches tall. What is the volume of the drinking glass ( assume cylinder) in cubic centimeters?

A) 170 cm3

B) 440 cm3

C) 350 cm3

D 710 cm3

E) 560 cm3

3. A woman walks 110 m in the direction 650 north of east, then 80 m directly east. Find the magnitude of the displacement vector A + B.

A) 84 m

B) 161 m

C) 245 m

D) 440 m

E) 558 m

4. A vector A in the x,y plane has an x component of -24 and an y component of 14 . The direction (angle the vector A makes with the positive x axis) of this vector is closest to:

A) 6°

B) 30°

C) 60°

D) 150°

E) 270°

5. A car moving initially at 10 m/s, travels 65 m along a straight line with constant acceleration for 5 s. The acceleration of the car is:

A) 0

B) 0.5 m/s2

C) 1.2 m/s2

D) 3.0 m/s2

E) 6.0m/s2

6. A car travels along east and its velocity decreases. The acceleration of the car is in which of the following directions?

A) Eastward

B) Westward

C) Northward

D) Southward

E) Southwest

7. A car is traveling at constant speed when the driver suddenly applies the brakes, giving the car constant deceleration of 3.5 m/s2. If the car stops in a distance of 30 m , what was the car’s original speed?

A) 10.2 m/s

B) 14.5 m/s

C) 25.0 m/s

D) 42.1 m/s

E) 54.7 m/s

8. 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

9. A stone is released vertically from a bridge above the water. If it takes for the stone 2.3 s to reach the water , what is the height of the bridge?

A) 10 m

B) 14 m

C) 26 m

D) 32 m

E) 56 m

10. An object is thrown vertically upward. While it is rising:

A) its velocity and acceleration are both upward.

B) its velocity is upward and its acceleration is downward.

C) its velocity and acceleration are both downward.

D) its velocity is downward and its acceleration is upward

E) its velocity and acceleration are both decreasing.

11. A bullet fired from the ground level at an angle of 350 above the horizontal. strikes the ground 10 seconds later. What is the magnitude of the bullet’s initial velocity ?

A) 11.4 m/s

B) 23.4 m/s

C) 35.4 m/s

D) 60.4m/s

E) 85.4 m/s

12. A rescue plane drops a package of emergency food to a stranded party of explores. If the plane is traveling horizontally at 85 m/s at a elevation of 625 m, how far horizontally from the release point does the package strike the ground?

A) 960 m

B) 680 m

C) 360 m

D) 240 m

E) 120 m

13. For general projectile motion, which statement is true when the projectile is at the highest point of its trajectory?

A) Its acceleration is zero.

B) Its velocity is perpendicular to the acceleration.

C) Its velocity is zero.

D) The horizontal and vertical component of its velocity are both zero.

E) Its velocity is parallel to the acceleration.

14. Agolf ball with an initial angle of 350 lands exactly 234 m down the range on a level course. What was its initial velocity?

A) 24.0 m/s

B) 35.0 m/s

C) 49.0 m/s

D) 58.0 m/s

E) 63.0 m/s

Workout problems:

1. ( 3 points) A stone is projected with an initial speed v0 = 22 m/s directed 350 above the horizontal, as shown in the figure. Half second later it strikes a cliff.

a. How high is the cliff?

b. How far horizontally from the release point does the stone hit the cliff?

c. What is the stone’s velocity just before it hits the cliff?

2. ( 2 points) Two vectors are acting on an object as shown. What are a) the magnitude and b) the

direction of resultant vectorF1 + F2?

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