Calculating Net Force
During a tug-of-war game, Team A pulls to the left with 60 N of force, and Team B pulls to the right with 55 N of force. What is the net force, AND which team is winning?
5 N to the left.
Team A is winning.
Which Law is this:
If an object is in motion, it will stay in motion. If an object is at rest, it will stay at rest.
a. Law of Inertia
b. Law of Acceleration
c. Law of Action and Reaction
A. Law of Inertia - Newton's First Law
A dog is pulling a sled across the snow. The sled has a mass of 6 kg and it accelerates at a rate of 4 m/s².
What is the force acting on the sled?
Force = mass × acceleration
Force = 6 kg × 4 m/s² = 24 N
Answer: 24 N
Jamal and his sister are moving a bookshelf. Jamal pushes to the right with a force of 40 N, but his sister is accidentally pushing to the left with a force of 10 N. What is the net force on the bookshelf, and which direction is it moving?
10 N to the right.
Which law is this? For every action, there is an equal and opposite reaction.
A. Law of Inertia
B. Law of Accelaration
C. Law of Action and Reaction
C. Law of Action and Reaction - Newton's Third Law
A horse pulls a small wagon with a force of 1200 Newtons. The wagon accelerates at 4 m/s². What is the mass of the wagon?
mass = force / acceleration = 1200N / 4 m/s² = 300 kg
Two movers are carrying a couch. One lifts up with 120 N of force, and the other supports from below with 100 N of force. Gravity pulls the couch down with 220 N of force. What is the net force acting on the couch?
Which law is this: The more force, the more acceleration
A. Law of Inertia
B. Law of Acceleration
C. Law of Action and Reaction
B. Law of Acceleration
A soccer player kicks a 40 kg cart with a force of 320 Newtons.
What is the acceleration of the cart?
Acceleration = Force / Mass
320 N / 40 kg = 8 m/s²
Question on Slide Show!!
Draw it and add another blue person.
Mr. Thompson is sledding down a hill and can’t stop in time. He crashes into a snowbank. His mass is 95 kg, and he hits the snowbank with an acceleration of 12 m/s².
What is the force Mr. Thompson experiences when he crashes?
Force = mass × acceleration
Force = 95 kg × 12 m/s² = 1140 N
1140 Newtons of force. OUCH!
Jason throws a tennis ball with a mass of 0.4 kg and it accelerates at 6 m/s².
Maya pushes a heavy box with a mass of 10 kg, and it accelerates at 1.5 m/s².
What are the forces acting on the tennis ball and the box?
Whose arms do you think feel more sore afterward? Why?
Tennis ball:
Force = 0.4 kg × 6 m/s² = 2.4 N
Box:
Force = 10 kg × 1.5 m/s² = 15 N
Maya likely feels more sore because pushing the heavier box requires more force (15 N vs. 2.4 N), which means more effort from her muscles.