Speed
A train moves at a constant velocity of 90km/h. How far will it move in .25 h?
22.5km
Michelle walks 100m toward the west, then turns and walks back the way she came 20m. What is her distance? What is her displacement?
120m, 80m West.
A object move with a constant acceleration of 6 m/s^2. What is true about its velocity?
Velocity increases by 6 m/s each second
Explain newtons 1st law of motion
An object at rest remains at rest, and an object in motion remains in motion at constant speed and in a straight line unless acted on by an unbalanced force.
Unit for work
J
A bicyclist moves a a constant speed of 6 m/s. How long will it take for the bicyclist to move 36 m?
6s
An Olympic runner competing in the 1600m circles the track exactly 4 times during a race. What is his distance? What is his displacement?
1600m, 0m.
An object is released from rest and falls in the absence of air resistance. What is true about its acceleration?
Its acceleration is constant
Explain newtons 2nd law of motion
(Force equals mass times acceleration)
Unit for Force
N
If a car travels 400m in 20 seconds how fast is it going?
S = d/t s = 400m/ 20 sec = 20m/s
Some hikers travel 2 km north, turn toward the west and travel 4km, turn toward the south and travel 6 km, then finally travel east for 4 km. What is their distance? What is their displacement?
16m, 4km South
In order for a rocket ship in deep space, far from any other objects to move in a straight line with constant speed it must exert a net force that is
zero
Explain newtons 3rd law of motion
for every action, there is an equal and opposite reaction
Unit for Acceleration
m/s2
You arrive in my class 45 seconds after leaving math which is 90 meters away. How fast did you travel?
2m/s
A shopper walks forward 20m, turns right and walks 5m, turns left and walks in the original direction 10m, then turns left again for 5m. What is her distance? What is her displacement?
40m, 30m forward (positive)
If a book on the dashboard of your car suddenly flies towards you, the forward velocity of the car must have
increased
A car travelling 40 m/s strikes a mosquito. Explain how much force is being applied to each?
equal force so 40 m/s
Units for Velocity
m/s
You need to get to class, 200 meters away, and you can only walk in the hallways at about 1.5 m/s. (if you run any faster, you’ll be caught for running). How much time will it take to get to your class?
T = d/s 200m/1.50m/s = 133.33s
Amy runs 2 miles south, then turns around and runs 3 miles north. Find displacement
1 North
A boy rides a bicycle at a constant velocity, What the is true about the net force.
It is zero
A soccer player kicks a soccer ball with a force of 1300 N. The soccer ball hits the player with a force of
1300N
What Units = Newtons
1kg x m/s2