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Homework Help: Help with some simple Physics pls.

  1. Sep 10, 2006 #1
    If anyone can help me with the following I would really appreciate it. I missed the first few weeks of class because my brother was in the hospital after a serious crash and I have a test coming up and I was given this quiz as a study guide. Most of the stuff is pretty introductory but I really dont know where to start. Any input is greatly appreciated and will help me to study for this test.. thanks.

    1. An automobile drive puts on the brakes and decelerates from 28 m/s
    to zero in 12 s. What
    distance does the car travel during this time?

    a. 168 m b. 196 m c. 336 m d. 392 m

    2. A model rocket, launched from the ground, rises vertically with
    acceleration of 30 m/s2 for
    two seconds when it runs out of "fuel". Disregarding air
    resistance, how high will the rocket
    be when it runs out of fuel?

    a. 15 m b. 30 m c. 60 m d. 120 m

    3. A 50-gram ball traveling at 25 m/s is bounced off a brick wall and
    rebounds at 22 m/s. A high
    -speed camera records this event. If the ball is in contact with
    the wall for 3.5 ms, what is the
    average acceleration of the ball during this time interval?

    a. 13,428 m/s2 b. 6,715 m/s2 c. 857 m/s2 d. 20

    4. A bird, accelerating from rest at a constant rate, experiences a
    displacement of 28 meters in
    11 seconds. What is the average velocity?

    a. 1.7 m/s b. 2.5 m/s c. 3.4 m/s d. zero

    5. Mt. Everest is more than 8000 m high. How fast would an object be
    moving if it could free
    fall to sea level after being released from the top of Mt.
    Everest? (Ignore air resistance)

    a. 396 m/s b. 120 m/s c. 1200 m/s d.
    12,000 m/s

    6. Human reaction time is usually about 0.15 s. If your lab partner
    holds a ruler between your
    finger and thumb and releases it without warning, how far can you
    expect the ruler to fall
    before you catch it? The distance is about:

    a. 8 cm b. 9 cm c. 10 cm d. 11cm

    7. Two objects of different mass are released simultaneously from the
    top of a 20 m tower and
    fall to the ground. If air resistance is negligible, which
    statement best applies?

    a. The greater mass hits the ground first.
    b. Both objects hit the ground together.
    c. The smaller mass hits the ground first.
    d. No conclusion can be made with the information given.

    8. Jeff throws a ball straight up. For which situation is the
    vertical acceleration zero?

    a. On the way up
    b. At the top
    c. On the way back down
    d. None of the above

    9. A European sports car dealer claims that his car will accelerate
    at a constant rate from rest
    to 100 km/hr in 8.0 s. If so, what is the acceleration? (Hint:
    First convert speed to m/s)

    a. 3.47 m/s2 b. 6.82 m/s2 c. 11.37 m/s2 d.
    17.40 m/s2

    10. The value of an object's acceleration may be characterized in
    equivalent words by which of
    the following?

    a. displacement
    b. rate of change of displacement
    c. velocity
    d. rate of change of velocity
  2. jcsd
  3. Sep 10, 2006 #2


    User Avatar
    Science Advisor
    Gold Member

    It's generally frowned upon to simply post questions without showing some effort.

    Look up your basic kinematics formulas. Lots of these are solved by just plugging in the numbers, but it helps to have an intuitive feel. Some of the formula you probably already know. velocity = distance / time. (Think of your car's speedometer. It gives you your velocity in miles / hour). velocity = acceleration * time will get you through a lot of these. Try some and post when you get stuck.
    Last edited: Sep 10, 2006
  4. Sep 10, 2006 #3
    Actually, my study guide consists of 48 diff questions and these are the ones Im a little confused on. Most the others are very simple. I just numbered them 1-10 for convenience. ty for the input. I will try some more tomorrow.. bedtime for now.
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