Balanced & Unbalanced Forces
What does Newton's First Law of Motion say?
An object at rest remains at rest, an object in motion remains in motions, unless acted upon by an unbalanced force
What is the formula for average speed?
Distance/Time
What is the formula for velocity?
Displacement/Time
How do you solve for total time?
Add all of the times together and divide by the total number
On a distance-time graph, what is on the x-axis?
Time
What is the definition of inertia?
The tendency for objects in motion to resist changes in direction and speed
Student 1: 15s/3m= 5s/m
Student 2: 15m x 3s= 45m/s
Student 3: 15m/3s= 5m/s
Student 4: 15m-5s= 10m/s
Which student completed the speed calculation correctly? How do you know?
Student 3 because distance is divided by time when speed is calculated
A plane was flying in southwestern direction at a rate of 35km/h represents which of the following:
A. Velocity
B. Speed
C. Time
D. Displacement
A. Velocity
A bus travels 135 miles in the first 2 hours, 80 miles in the next 1 hour, and 50 miles in the last hour. What is the average speed of the bus?
66.25mph
On a distance-time graph, what is on the y-axis?
Distance
If a ball is rolling to the right, what unbalanced force must be acting on it?
A. 50 East
B. 40 West
C. 35 North
D. 60 South
A. 50 East
4 students ran a 180-meter course during athletics.
Student 1: 30 seconds
Student 2: 28 seconds
Student 3: 45 seconds
Student 4: 33 seconds
How much faster was the average speed for Student 1 compared to Student 3?
2m/s
25 m/s West, 12km/h East, 35 m/m South
Are these examples of speed or velocity? How do you know?
Velocity because it has speed and direction
Which has the greatest average speed?
A. A train traveling 100km in 10 hours
B. A car driving 125km in 5 hours
C. A boat sailing 60km in 4 hours
D. A plane flying 30km in 6 hours
B. A car driving 125km in 5 hours
What does a steep slope represent? What does a shallow slope represent?
Steep slope= faster speed
Shallow slope= slower speed
A marble was pushed by two students in opposite directions. Student A pushed the marble 150N to the right and Student B pushed the marble 129N to the left.
What is the net force of the marble?
It will move towards the right 21N.
25 m/s, 10 m/m, 12 km/h
Are these examples of speed or velocity? How do you know?
Speed only tells distance and time
An airplane leaves the DFW airport and flies 125km to Houston. After 5 hours, the airplane returns back to DFW airport. What is the average speed? What is the displacement?
Average speed- 25 km/h
Displacement- 0 km/h
A runner travels 150 meters west in 10 minutes, then 450 meters west in 30 minutes. What is their average speed for the entire trip? What is the velocity?
Average speed- 15 m/m
Velocity- 15 m/m West
If a distance-time graph shows a line that goes downwards, what does this indicate about the object's motion?
A) The object is moving away from the starting point.
B) The object is returning to the starting point.
C) The object is moving faster.
D) The object is at rest.
B. The object is returning to the starting point
A pencil was sitting on the table motionless and not touched by an outside force will MOST likely remain motionless because...
Balanced forces exerted by gravity and the table keep the paper motionless
In a 200-meter race, a person travels the first 100 meters in 50 seconds, 50 meters in 30 seconds, and the remaining 50 meters in 10 seconds. Calculate the average speed of the runner.
6.67 m/s
Student A and Student B started at the same point on the track and ran at the same speed in opposite directions, explain the difference in their velocities.
One student would be running in a positive direction and one student would be running in a negative direction
A distance-time graph shows that an object moves 80 meters in the first 2 minutes and then remains stationary for the next 3 minutes. What is the average speed for the entire 5 minutes?
A) 16 m/min
B) 32 m/min
C) 40 m/min
D) 80 m/min
A. 16m/min
If a distance-time graph shows a series of steep and shallow slopes, what does this suggest about the object's speed?
A) The object is moving at a constant speed.
B) The object is changing speed.
C) The object is stationary.
D) The object is moving backwards.