Measurements
What is the common unit of distance in Physics?
Meters
What does the distance over time define?
Velocity and/or Speed
What does the change in velocity over time define?
Acceleration
What is Newton's second law of motion?
Force = mass x acceleration
A cart crashes into another cart and they bounce off of each other. What type of collision is this?
Elastic Collision
What is an appropriate unit to measure time in?
Seconds, Minutes, or Hours (Also: Days, Weeks, Years)
How is Velocity different from Speed?
Velocity has direction and magnitude, while speed only has magnitude.
True or False: If an object in motion is changing direction, it is accelerating.
True
What is the acceleration due to gravity (g) on Earth?
9.8 m/s/s
A cannonball is fired from a cannon.
What type of collision is this?
Explosion Collision
True or False: The appropriate units to measure velocity in is seconds per meter (s/m).
False. The appropriate units to measure velocity in is meters per second (m/s).
Draw a strobe picture of a car driving at a constant velocity.
If the velocity is constant, then the acceleration is ________
Zero
A box is being pushed from the left with a force of 300 Newtons. What amount of force from the right would be needed to keep the box in equilibrium?
300 Newtons.
A 500 kg car is moving at a speed of 30 m/s. What is its momentum?
G: m = 500kg, v = 30 m/s
U: P = ?
E: P = mv
S: P = (500)*(30)
S: P = 15,000 kg m/s
Convert 5,000 grams to kilograms.
5,000 grams = 5 kg.
Draw a Position vs. Time Graph that demonstrates a constant velocity.
Draw a Velocity vs. Time graph that demonstrates an object moving with constant velocity.
The mass of a box is 5 kg. If that box is on Earth, what is its weight (Fg)?
1. m = 5 kg g = 9.8 m/s/s 2. Fg = ? 3. Fg = mg 4. Fg = (5 kg) x (10 m/s/s) 5. Fg = 49 Newtons
Which object would have the greatest momentum?
a. A 5 kg bowling ball moving at 7 m/s
b. A 0.4 kg bird flying at 30 m/s
c. A 20 kg wheelbarrow moving at 2 m/s
d. A 0.3 kg baseball batted at 60 m/s
c. A 20 kg wheelbarrow moving at 2 m/s
Which gives you a more accurate measurement of the length of a pencil? A meter stick, or a centimeter ruler?
A centimeter ruler.
Lupita walked to school with an average speed of 2 meters per second. The distance from Lupita's house to school was about 1200 meters. Use the five step method to determine how long it took for Lupita to reach school.
1. v = 2 m/s d = 1200 m 2. t = ? 3. t = d/v 4. t = 1200 m / 2 m/s = 600 s
Describe the motion of this object: https://drive.google.com/open?id=1lEwz324BcAgXc-XLTx8NTwaX__ZWYc3A
The object starts out fast, and then gets slower.
A weight lifter is accelerating a 50 kg dumbbell upwards at 12m/s^2. Determine the net force applied on the dumbbell, and determine what direction it is going in.
G: m = 50 kg, a = 12 m/s^2, g = 9.8 m/s^2
U: F1 = ?, Fg= ?, Fnet = ?
E: F = ma, Fg = mg
S: F1 = 50*12, Fg = 50*-9.8, Fnet = F1+Fg
S: F1 = 600 N, Fg = 490 N, Fnet = 110 N
A 60 kg person initially going at a speed of 0.25m/s grabs a stationary 10 kg shopping cart. The person holds on to the cart and continues to travel in the same direction. What is the speed of the person and the cart after the collision?
G: m1 = 60 kg, m2= 20 kg, v1i=0.25 m/s, v2i=0m/s
U: vf = ?
E: m1v1i + m2v2i = (m1 + m2)vf
S: 15 + 0 = 80 vf
S: vf = 0.19 m/s