Force, Motion, Speed, Velocity (2.1 and 2.2)
The SI Unit for the strength of a force is called...
Newtons (N)
If you were given a negative value for acceleration, this means that the object is...
(speeding up/ slowing down/ moving backwards/ changing direction)
slowing down
According to Newton's 2nd Law of Motion, Force equals mass times...
acceleration.
Which of the following are examples of non-contact forces?
gravity
friction
magnetism
electrical forces
gravity, magnetism, electrical force
If two forces acting on an object are equal in strength and opposite in direction, they are ____________ forces with a net force of ___.
balanced, 0 N
Suppose two teams are playing a game of tug-of-war. One team is pulling the rope to the left with a combined force of 50 N, while the other team is pulling the rope to the right with a combined force of 45 N. What is the net force in this scenario?
5 N to the left
What is the difference between scalar quantities and vector quantities?
Scalar quantities are measured by magnitude only. Vector quantities are measured by both magnitude and direction.
Which of Newton's 3 Laws of Motion is described by the following statement:
For every action, there is an equal (in magnitude) and opposite (in direction) reaction.
Newton's 3rd Law of Motion
The scientific law that states that the force of gravity acts between all objects in the universe that have mass is called...
the Law of Universal Gravitation.
What is the difference between speed and velocity?
Velocity also has a direction, speed does not.
Suppose a marble moved down a track at a speed of 3.2 m/s in 14 seconds. Based on this information, how long was the marble track?
44.8 m
speed = distance ÷ time
Suppose a runner was participating in a race. The runner traveled 5 km north, and then 12 km east. What was the displacement of the runner, and what was the runner's distance traveled?
Displacement: 13 km NE
Distance: 17 km
Which of Newton's 3 Laws of Motion is described by the following statement:
If an object is not moving, it will not start moving until an unbalanced net force acts on it. If an object is moving, it will continue at a constant velocity until a net force acts to change its speed or its direction.
Newton's 1st Law of Motion (law of inertia)
The average weight of a newborn baby is 31 Newtons.
Based on this information, what is the average mass of the newborn baby?
weight = mass x acceleration due to gravity
31 N = mass x 9.8 m/s2
mass = 3.2 kg
What is the name of the tool that would be used in the lab to measure force? What is the SI Unit for force?
spring scale; Newtons (N)
What is the acceleration due to gravity on Earth? (don't forget to include units!)
9.8 m/s2
Suppose an airplane is traveling at 80 m/s. To prepare for landing, it decreases its speed to 50 m/s in 120 s.
Based on this information, the acceleration of the airplane is...
-0.25 m/s2
acceleration = (final speed - initial speed)÷ time
Layla enjoys playing lacrosse on the school team. Suppose Layla throws a lacrosse ball with force of 6 N, and the resulting acceleration is 43 m/s2. The mass of the lacrosse ball is
0.14 kg
*DAILY DOUBLE!* Write your group's wager on your board (If you have $0, you may wager up to $500, but be prepared to lose it if you get it wrong!)
Is gravity a scalar quantity or a vector quantity? Explain your answer.
Which of the following statements is not true about gravity?
a. The greater the distance between two objects, the greater the gravitational force between them.
b. The more mass an object has, the greater the gravitational force between it and other objects.
c. Since gravity is a force, it can be measured in Newtons (N).
d. All objects in the universe that have mass have a gravitational pull toward one another.
a. The greater the distance between two objects, the greater the gravitational force between them.
*DAILY DOUBLE!* Write your group's wager on your board (If you have $0, you may wager up to $500, but be prepared to lose it if you get it wrong!)
Suppose you drove a distance of 3 km in 1 hr while in heavy traffic. Then, it took you 1 hr to drive 50 km from one side of a city to the other. Finally, you traveled 211 km on an interstate highway in 2 hrs. The average speed of your trip was...
What are the 3 factors that can cause a change in acceleration?
- Increase speed
- Decrease speed (decelerate/ negative acceleration)
- Change direction
Suppose a student kicks a soccer ball. Which of the following statement would not be true based on Newton's 3 laws of motion?
a. The greater force you apply to the soccer ball, the greater the acceleration of the ball.
b. When you apply a force to the soccer ball, the soccer ball applies a reaction force back on you.
c. The greater the mass of the soccer ball, the less force is required to move it.
d. The ball will stay still until you apply an unbalanced net force onto it with your foot.
c. The greater the mass of the soccer ball, the less force is required to move it.
Which of the following would cause an increase in the strength of the gravitational attraction between two objects? **SELECT ALL THAT APPLY**
a. Increase the distance between the two objects.
b. Decrease the mass of one of the objects.
c. Increase the mass of one of the objects.
d. Decrease the distance between the two objects.
c. Increase the mass of one of the objects.
d. Decrease the distance between the two objects.
Suppose a 1200 kg vehicle is driving at a constant velocity of 20 m/s east. What is the vehicle's:
- speed?
- velocity?
- acceleration?
- weight?
- net force?
*Hint: Remember to include units (and direction, when applicable)
- speed: 20 m/s
-velocity: 20 m/s east
- acceleration: 0 m/s2
- weight: 11,760 N
- net force: 0N (Remember: F=ma)