Your Name: _______________________ PHY203

Exam #1

Chapters 1-3

Thurs., 9/29/05

Lecture Time: 9 a.m 1p.m. 2p.m. 3p.m. Honors

Score:

1-10 _________________ (out of 30) (3 x ____ )

11 _________________ (out of 30)

12 _________________ (out of 40)

Total _______________

Multiple choice answer sheet-shade in correct answers below

(one choice per problem):

	1	2	3	4	5	6	7	8	9	10
a
b
c
d
e

1. A football field is 100 yards long. How many centimeters is that?

a. 91,440 cm

b. 9144 cm

c. 91.4 cm

d. 10,936 cm

e. 109,360 cm

2. Convert a speed of 55 miles/hr to m/s:

a. 1.47 m/s

b. 9.5 m/s

c. 24.6 m/s

d. 570 m/s

e. 1476 m/s

3. Write 200 femtometers in correct SI units:

a. 2x10^-9 m

b. 2x10^-11 m

c. 2x10^-13 m

d. 2x10^-15 m

e. 2x10^-17 m

4. Write 0.013 gigakilograms in correct SI units:

a. 1.3x10⁶ kg

b. 1.3x10⁷ kg

c. 1.3x10⁹ kg

d. 1.3x10¹⁰ kg

e. 1.3x10¹¹ kg

5. Convert an acceleration of 4500 km/hr² to m/s²:

a. 0.015 m/s²

b. 0.35 m/s²

c. 1250 m/s²

d. 5.8x10⁷ m/s²

e. 3.47x10^-7 m/s²

For questions 6 and 7:

At t = 0, the speed of an object starting from the origin is 50 m/s at an angle of 30^o with respect to the x-axis. At t=3 sec., the particle is at x= 3m and y= -6m with a speed of 45 m/s at an angle of 45^o with respect to the x-axis.

6. Find the average velocity over the time interval:

a. 47.5 m/s

b. 31.7 m/s

c. 1 m/s i –2 m/s j

d. -1 m/s i +2 m/s j

e. 9 m/s i –18 m/s j

7. Find the average acceleration over the time interval:

a. 47.5 m/s²

c. -4.8 m/s² i +2.3 m/s² j

c. -3.8 m/s² i +2.3 m/s² j

d. -4.8 m/s² i +3.3 m/s² j

e. -3.8 m/s² i +3.3 m/s² j

For questions 8-10:

A person’s path is plotted above.

8. Find the total displacement:

a. -10,000 m

b. -5000 m

c. 0 m

d. 5000 m

e. 10,000 m

9. Find the total average speed:

a. 0 m/s

b. 0.8 m/s

c. 0.265 m/s

d. 1.6 m/s

e. 95.2 m/s

10. Find the total average velocity:

a. 0 m/s

b. 0.8 m/s

c. 0.265 m/s

d. 1.6 m/s

e. 95.2 m/s

Your Name: _______________________

11. Let A = 5i + 3j, B = -2i + 4j, C = A – 2B

a. Sketch and clearly label the vectors A and B on the above graph.

b. For the vector A, find the magnitude of the vector and the angle the vector makes

with respect to the x-axis.

c. For the vector B, find the magnitude of the vector and the angle the vector makes

with respect to the x-axis.

d. Write the vector, C, in vector notation.

e. For the vector C, find the magnitude of the vector and the angle the vector makes

with respect to the x-axis.

f. Sketch and clearly label the vector C on the above graph.

Your Name: _______________________

12. A projectile is shot in a horizontal direction from a height of 350m and initial

speed of 50m/s, as shown above. (Note: Use 9.81 m/s2 for the magnitude of g, the

acceleration due to gravity.)

a. Write the initial velocity vector, v_o, in vector notation.

b. Calculate the time in sec. that it will take for the projectile to hit the ground.

c. Calculate the x position at which the projectile will hit the ground (the “range”).

d. Calculate the final velocity in the x-direction of the projectile just before it hits the

ground (magnitude and direction-use coordinate system above).

e. Calculate the final velocity in the y-direction of the projectile just before it hits the

ground (magnitude and direction-use coordinate system above).

f. Write the final velocity, v_f, of the projectile just before it hits the ground in vector

form and calculate the final speed.

PHY203

Exam #1

Crib Sheet

Chapters 1-3

speed_AV = (total distance traveled)/Dt

Dx = x₂ – x₁ (displacement)

v_AV = Dx/Dt

a_AV = Dv/Dt

v_Inst = dx/dt

a_Inst = dv/dt

For constant acceleration:

x_f = x_o + v_ot + (1/2)at2

v_f = v_o + at

V_f2 = v_o2 + 2a(x_f - x_o)

g = 9.81 m/s2, the acceleration due to gravity

For a vector A with magnitude A and direction q (measured counterclockwise with respect to the x-axis):

A_x = Acos(q)

A_y = Asin(q)

A = (A_x² + A_y²)^1/2

tan(q) = A_y/A_x

quadratic eq. sol.: If ax² + bx + c = 0; then x = -b+(b²-4ac)^1/2/(2a)