### Which of these is necessary for a reasonable order-of-magnitude estimate of the speed of a falling object?

Timeļ¼2012-10-20 00:55:30 +0000 - 1 year ago
1. Which of these is necessary for a reasonable order-of-magnitude estimate of the speed of a falling object?

Round all numbers to the nearest whole number.
Have a correct and exact value for the distance of the fall.
Use numbers for the time and distance of the fall that are reasonable even if inexact.
Assume that any falling object takes about a second to reach the ground.

2. What must you do to calculate a meaningful value of distance from the following equation?
dfinal = (0.90 km) + (12.5km/h) * (31.5 s)

Drop the symbols for the units.
Convert all times to either hours or seconds.
Convert kilometers to miles.
Convert the kilometers to meters.

3. Use the following equations to solve the problem.
final distance = initial distance + (speed * time)
df = di + vt
1.00 mi = 1.61 km

For an initial distance of 11.3 km, a speed of 35.0 miles per hour, and a time of 3.00 hours, what is
the final distance in km??

49.3 km
180 km
116 km
76.5 km

4. Suppose you are using a system of units based on the centimeter (cm) for length, the gram (g) for mass, and the second (s) for time. The kinetic energy that an object has because of its motion is equal to half its mass times its speed squared, or KE = 1/2mv2. In this system of units, what units would be used to express KE?

g*cm^2/s^2
g*cm/s
kg*cm^2/s^2
g*cm^3/s

5. Which of these units results when a distance of 35 m is multiplied by a force of 27 N, and then divided by a time of 5 s? A newton (N) is kg*m/s^2 in SI base units.

kg^2 * m/s
kg * m^2/s^2
kg * m/s
kg * m^2/s^3

10 points!! PLEASE help.. Nobody my age needs to learn physics. Nobody any age needs to learn physics unless you're planning to major in it... Please, Please, Help!!! :(

These questions aren't really Physics.
They are something between reading comprehension and high school level English comprehension.
Up to a point; there's some elementary logic.
Think of them as little puzzles.