PHYS 1200 Lecture Notes - Lecture 3: Escape Velocity

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aquamarinesnake56

18 Aug 2016

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The larger the area of the object is, the more air resistance, due to the fact it has to push more molecules out of the way of its path (that is why not all objects fall at. Acceleration is the rate at which the velocity changes with time (increases or decreases) Acceleration measured in units divided by time squared (m/s^2, cm/s^2, etc ) A= change in velocity/ change in time: final velocity = initial velocity + acceleration x time, xsubf = xsubi +vt. Deceleration means that the acceleration is opposite in direction to the velocity (opposite signs) If the ball is dropped from rest, that means that its initial velocity is zero: so then new equation would be: final velocity = acceleration x time. As an object rises, it slows down, decelerates, because gravity is pulling it down: the object reaches it"s maximum height when v=o, since final velocity is 0, new equation is .

Related Questions

Note: Use principles of physicsto solve the problem and then verify your answer using thesimulation.
(a) In this simulation the acceleration in the y-direction is givenby ay = -9.8 m/s2 - c vy, where c is the value set by the airresistance slider. Which graph below represents the accelerationvs. time when air resistance is turned on for an object releasedfrom rest?

1Graph A
Graph B
Graph C
Graph D

(b) What is the largest magnitude the acceleration can have in thissimulation, considering the limits imposed by the sliders?
2 m/s2

(c) If the mass was allowed to fall for a long time with airresistance turned on it would reach a terminal (constant) velocity.If the air resistance slider is set to c = 0.40 what would thatterminal velocity be? (Hint: consider the equation given in part(a).)
3 m/s
(d) Run the simulation with air resistance turned off and with theinitial Y-Velocity set to +10 m/s. Run it a few more times,changing only the setting of the air resistance each time. When doall the graphs of Y-Velocity vs. time have the same slope?
4At the start, when t = 0
At the end of the motion
When t = 1 second
When the velocity graphs cross the time axis
None of the above

(e) What is the value of this slope?
5 m/s2

1. What is the difference between speed and velocity?

a. Speed is an average quantity while velocity is not.

b. Velocity contains information about the direction of motion while speed does not.

c. Speed is measured in mph, while velocity is measure in m/s.

d. The concept of speed applies only to objects that are neither. speeding up or slowing down, while velocity applies to every kind of motion.

e. Speed is used to measure how fast an object is moving in a straight line, while velocity is used for objects moving along curved paths.

2. The quantity 2.67 x 10³ has how many significant figures?

3. If Libby walks 100 m to the right, then 200 m to the left, her net displacement vector points

a. to the right.

b. to the left.

c. has zero length.

d. cannot tell without more information.

4. Velocity vectors point

a. in the same direction as displacement vectors.

b. in the opposite direction as displacement vectors.

c. perpendicular to displacement vectors.

d. in the same direction as acceleration vectors.

e. velocity is not represented by a vector.

chocolatemouse942

1. If an object moves with constant acceleration, its velocity a) must be constant also b) always decrease c) increases by the same amount each second d)change by varying amount depending on its speed.

2. A man leans over the edge of a cliff and throws a rock upward at 4.9 m/s. Neglecting air resistance, two seconds later the rock's speed is a) 9.8 m/s b) 14.7 m/s c) 4.98 m/s d) zero e) none of the above

3. Twelve seconds after starting from rest, an object falling freely will have a speed of a) 10 m/s b) 50 m/s c) more than 100 m/s d)100 m/s.

4. A ball is thrown 125 meters upward and then falls the same distance back to Earth. Neglecting air resistance, its total time in the air is about 10 seconds. about 15 seconds. about 5 seconds. more than 20 seconds.

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PHYS 1200 Lecture Notes - Lecture 3: Escape Velocity

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