Help with some simple Physics pls.

  • Thread starter wakejosh
  • Start date
  • #1
102
0
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
m/s2


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
 

Answers and Replies

  • #2
tony873004
Science Advisor
Gold Member
1,751
143
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:
  • #3
102
0
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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