Physics 1131 Homework 1 Due: 9/4 Name __________________

Part 1:

1. Convert 152 mi/h to m/s

2. Convert 4.50×103 kg/m3 to g/cm3

3. Simplify 5.2 x 104 in scientific notation

1.3x 10-3

Review the following link, complete problems 4 – 8

4. A 3 kg object is 2 m right of a wall. Four seconds later, the object is 10 m right of the wall. a) What is the object’s initial position? b) What is the object’s final position? c) What is the object’s displacement? d) What is the magnitude of the object’s displacement? e) What is the object’s velocity? f) What is the object’s speed?

5. A 5 kg object is 10 m left of a wall. Five seconds later, the object is 5 m right of the wall. a) What is the object’s initial position? b) What is the object’s final position? c) What is the object’s displacement? d) What is the magnitude of the object’s displacement? e) What is the object’s velocity? f) What is the object’s speed?

6. A 10 kg object is 100 m north of a fence. Ten seconds later, the object is 50 m north of the fence. a) What is the object’s initial position? b) What is the object’s final position? c) What is the object’s displacement? d) What is the magnitude of the object’s displacement? e) What is the object’s velocity? f) What is the object’s speed?

7. A 3 kg object is 10 m right of a wall. Four seconds later, the object is 2 m right of the wall. a) What is the object’s initial position? b) What is the object’s final position? c) What is the object’s displacement? d) What is the magnitude of the object’s displacement? e) What is the object’s velocity? f) What is the object’s speed?

8. A 10 kg object is 20 m right of a wall. Five seconds later, the object is 20 m left of the wall. a) What is the object’s initial position? b) What is the object’s final position? c) What is the object’s displacement? d) What is the magnitude of the object’s displacement? e) What is the object’s velocity? f) What is the object’s speed?

Part 2:

1. Convert 25 cm into inches

2. Convert 3 mi into m.

3. Convert 3 ft into m.

4. Convert 3.5 hours into seconds.

5. Convert 275 grams into kilograms.

6. Convert 13.5 cm into m.

7. Convert 40 mi/h into m/s.

8. Convert 20 m/s into mi/h.

All terms of an equation must have the same dimensions to be physically valid. If you are going to add terms, then the units of the terms must be the same. In the following problems, the variables used have the dimensions and SI units shown in the table below. Assume all units in the problems are SI and all equations are physically valid.

Topic | Dimensions | SI Units | Variables |

Time | T | s | t |

Mass | M | kg | m |

Position | L | m | x, y, z |

Displacement | L | m | D |

Speed | L/T | m/s | v |

Velocity | L/T | m/s | v |

Momentum | M.L/T | kg.m/s | p |

Acceleration | L/T/T or L/T2 | m/s/s or m/s2 | a |

Force | M.L/T2 | kg.m/s2 | F |

Work, Energy | M.L2/T2 | kg.m2/s2 | W, PE, KE |

1. In the equation D = vt a) What are the SI units of D? b) What are the SI units of v? c) What are the SI units of t?

2. In the equation x = xo + vt a) What are the SI units of x? b) What are the SI units of xo? c) What are the SI units of v? d) What are the SI units of t?

3. In the equation v = vo + at a) What are the SI units of v? b) What are the SI units of vo? c) What are the SI units of a? d) What are the SI units of t?

4. In the equation x = 10 + 8t + 9t2 a) What are the SI units of x? b) What are the SI units of t?

5. In the equation D = 3t + 6t2 a) What are the SI units of D? b) What are the SI units of t?

6. In the equation p = mv a) What are the SI units of p? b) What are the SI units of m?

7. In the equation p = 5v a) What are the SI units of p?

8. In the equation p = Ft a) What are the SI units of p? b) What are the SI units of F? c) What are the SI units of t?

Physics 1131 Lab 1 Due: 9/4 Name ________________________

Constant Velocity and Momentum

After this lab you should understand how to:

1. Recognize what a marked video screen looks like for constant velocity.

2. Recognize what a position versus time graph looks like for constant velocity.

3. Recognize what a displacement versus time graph looks like for constant velocity.

4. Find the velocity from a position or displacement versus time graph.

5. Analyze a position versus time graph and write position and displacement equations as functions of velocity and time.

6. Use conversions.

7. Find momentum from velocity or find velocity from momentum.

8. Understand that the area of a velocity versus time graph is displacement.

9. Understand that the area of a momentum versus time graph is mass times displacement.

Experimental Steps:

PTK60 ->auto->Browser->OK->Algebra Physics->Constant Velocity->A van travels in the position x direction->Marking the video->Click here to open the video->Yes

1. Play the video.

2. Press the Next button.

3. Select Option 1, then press the Next button.

4. Pick the x direction of motion, then press the Next button.

5. Select position, velocity and momentum plots, then press the Next button.

6. Press the graph button.

If you use online PTK60 version:

PTK60.com->Physics 1100->Constant Velocity-> A van travels in the position x direction->play->Next->Click the button “Slope Off” change to “Slope On”

7. Is the velocity constant? What tells you this?

8. Is the velocity positive or negative? What tells you this?

10. Write an equation for position (x = xo + vt) and check your equation with at least two different times on the graph.

11. Write an equation for displacement (D = vt) and check your equation with at least two different times on the graph.

12. Look at the velocity versus time graph. What are the units of the area?

13. Use the velocity versus time graph and the Area Button to find an area for some Δt. (Click Area Button, select Automatic Calculation, left click one point and right click another point on the line to get value of area.) or (Online version: Click the button “Area Off” change to “Area On”, then left click one point and right click another point on the line to get value of area)

14. Examine the momentum versus time graph. Does it have the same shape as the velocity versus time graph? Are the numbers the same? Are the units the same? How do you go from the velocity graph to the momentum graph? How do you go from the momentum graph to the velocity graph?