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Problem Solving Task 1 2014

Due: 11:59pm on Friday, March 28, 2014

You will receive no credit for items you complete after the assignment is due. Grading Policy

Question 1

Starting from home, you bicycle 26km north in 2.4h and then turn around and pedal straight home in 1.4h . What are your (a) displacement at the end of the first 2.4h , (b) average velocity over the first 2.4h , (c) average velocity for the homeward leg of the trip, (d) displacement for the entire trip, and (e) average velocity for the entire trip?

Part A

Express your answer using two significant figures. Assume North as positive direction.

ANSWER:

26 |   km   |

Correct

Part B

Express your answer using two significant figures. Assume North as positive direction.

ANSWER:

11 |   km/h   |

Correct

Part C

Express your answer using two significant figures. Assume North as positive direction.

ANSWER:

-19 |   km/h   |

Correct

Part D

Express your answer using two significant figures. Assume North as positive direction.

ANSWER:

0 |   km   |

Correct

Part E

Express your answer using two significant figures. Assume North as positive direction.

ANSWER:

0 |   km/h   |

Correct

Question 2

Starting from rest, a subway train first accelerates to 29m/s and then begins to brake. Forty-eight seconds after starting, it is moving at 12m/s .

Part A

What is its average acceleration in this 48-s interval?

Express your answer using two significant figures.

ANSWER:

a¯ =  | 0.25 |   m/s2   |

Correct

Question 3

You're driving at 80km/h when you accelerate with constant acceleration to pass another car. Six seconds later, you're doing 88km/h .

Part A

How far did you go in this time?

Express your answer using two significant figures.

ANSWER:

Δx =  | 140 |   m   |

Correct

Question 4

A rocket rises with constant acceleration to an altitude of 95km , at which point its speed is 3.2km/s .

Part A

What is its acceleration?

Express your answer using two significant figures....