Your Name: _______________________ PHY203

Final Exam

Student ID: ________________________ Chapters 1-12,14

12/12/03

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

Part 1 Part 2

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Part 3 Part 4

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Your Name: _______________________ PHY203

Final Exam

Student ID: ________________________ Chapters 1-12,14

12/12/03

Part 1

Part 2

1. A block of mass 5 kg is attached to a spring and sitting on a horizontal frictionless surface. It requires a force of 10 N to stretch the spring by 10 cm. Calculate the spring constant of the spring:

a. 1.0 N^.m

b. 2.0 N^.m

c. 20 N^.m

d. 100 N^.m

e. 1000 N^.m

(For Problems 2 and 3)

A 2 kg mass is attached to a string and spun around on a frictionless horizontal surface fast enough such that the centripetal acceleration is 5g.

2. Calculate the magnitude of the centripetal force:

a. 5 N

b. 24.5 N

c. 49.0 N

d. 98.1 N

e. 196.2 N

3. If the radius of the circle is 0.5 m, calculate the speed of the mass:

a. 2.48 m/s

b. 3.50 m/s

c. 4.95 m/s

d. 7.00 m/s

e. 9.90 m/s

(For problems 4 and 5)

A block of mass 10 kg is on a rough surface. The maximum (or critical) frictional force is 20N. The kinetic frictional force is 15N.

4. You pull on the block with a horizontal force of 10N in the positive x direction; calculate the magnitude of the acceleration of the block:

a. 0 m/s²

b. 0.5 m/s²

c. 1.0 m/s²

d. 1.5 m/s²

e. 2.0 m/s²

5. You pull on the block with a horizontal force of 50N in the positive x direction; calculate the magnitude of the acceleration:

a. 3.0 m/s²

b. 3.5 m/s²

c. 5.0 m/s²

d. 6.0 m/s²

e. 7.0 m/s²

(For problems 6 and 7)

An external force, F, of magnitude 10N is applied to a 20kg block at an angle of 30o with respect

to the horizontal, as shown below. Assume the surface under the mass is frictionless.

6. Calculate the normal force on the block :

a. 187.5 N

b. 191.2 N

c. 196.2 N

d. 201.2 N

e. 204.9 N

7. Calculate the acceleration of the block in the x-direction:

a. 0.25 m/s²

b. 0.43 m/s²

c. 0.50 m/s²

d. 0.58 m/s²

e. 1.0 m/s²

(For problems 8 and 9)

A block of mass 15 kg slides down a frictionless ramp making an angle of q = 30^o with the

horizontal, as shown below.

8. Calculate the acceleration of the block down the ramp.

a. 2.45 m/s²

b. 4.9 m/s²

c. 8.5 m/s²

d. 9.8 m/s²

e. 73.5 m/s²

9. Calculate how far the block will travel along the ramp from rest in a time of 1.5 s:

a. 2.78 m

b. 5.5 m

c. 9.6 m

d. 11 m

e. 83 m

(For problems 10-12)

A block of mass 5.0 kg has a speed of 10 m/s at point A. The block slides 2 meters on a rough surface which has a kinetic friction coefficient of m_k = 0.25. The block travels 2 meters over a frictionless surface between points B and C and then encounters a spring with spring constant, k=8000 N/m.

10. Calculate the kinetic energy of the block at point A:

a. 25 J

b. 50 J

c. 125 J

d. 250 J

e. 500 J

11. Calculate the energy converted by friction to heat by the block sliding on the rough surface:

a. 6.1 J

b. 12.3 J

c. 24.5 J

d. 49.0 J

e. 98.1 J

12. Calculate compression of the spring when the block comes (momentarily) to rest:

a. 0.028 m

b. 0.031 m

c. 0.24 m

d. 0.25 m

e. 0.75 m

PHY203

Final Exam, F/03

Crib Sheet #2

Chapters 4-7

(Note: Use 9.81 m/s2 for g, the acceleration due to gravity.)

For constant acceleration(in one dimension):

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

v_f = v_o + at

v_f2 = v_o2 + 2a(x_f - x_o)

(Note: Bold letters indicate vectors below.)

F = ma

spring force: F = -kDx , where k is the spring constant

weight: W = mg

friction force:

kinetic fk = mkFn , where Fn is the normal force and mk is

the kinetic frictional coefficient

static fs < msFn, fsmax = msFn

uniform circular motion

centripetal acceleration: a = v2/R

Work and Energy

W = F ^. d = Fdcosq

Work done by friction = -f_kDs

E_Thermal = |Work done by friction|

Kinetic Energy: K = (1/2)mv²

Potential Energy: U_spring = (1/2)kx²

U_grav = mgh

Total energy, E, is conserved ( a constant).

Power = Work/Time