NEWTON S LAWS OF MOTION
Force The ability to cause a change in a state of motion of an object (Vector) The only thing that can cause an object to accelerate is a Force
An object at rest will remain at rest and an object in motion will maintain a constant velocity unless acted upon by a net external force Law of Inertia The tendency of an object to resist a change in motion
F = ma
For every action force there is an equal and opposite reaction force There is no such thing as a lone force, all forces come in pairs
3 people push on a boat that is 752 kg. The boat floats next to a dock. Each of the people push on the boat with 80.5N of force parallel to the dock. (A) What is the acceleration of the boat if they all push in the eastern direction? (B) What is the magnitude and direction of the boat s acceleration if 2 of the people push in the west direction and one of the people push toward the east?
Gilgur yells at his twins for the messy house. The twins decide to pack their stuff on a wagon and run away. The cart starts at rest and pulls on the cart for 25m reaching a speed of 6 m/s. With what force did they pull on the wagon?
Velocity on impact = 123 km/hr (34.2 m/s) Find Force exerted on cliff jumper? Time it takes to come to a complete stop: 2.6s Mass: About 170 pounds (77.1 kg)
Gilgur is ice skating with his twins. After a while it s time to go home, but they don t want to So Gilgur needs to start dragging his kids with a constant horizontal force of 50N, the kids start to accelerate at 1.3 m/s^2. If his son has a mass of 22.6 kg, what is the mass of the daughter?
1) If Mr. Burns pulls on a.3kg pillow in opposite directions with 10 N and his wife pulls on it with 11 N, what is the horizontal acceleration of the pillow? Answer: 3.33 m/s^2 2) You are pulling your little sister on her sled. When you exert a constant horizontal force of 110 N, the sled has an acceleration of 2.5 m/s^2. If the sled has a mass of 7 kg, what is the mass of your little sister? Answer: 37kg
A pitcher throws a 0.15kg baseball that gets displaced 2m, accelerating it from rest to a speed of about 90 mi/hr (40 m/s). Estimate the force exerted by the pitcher on the ball
Two groups of canoeists meet in the middle of a lake. A person in canoe 1 pushes on canoe 2 with a force of 46 N to serperate the canoes. If the mass of canoe 1 and its occupants is m1 = 150kg, and the mass of canoe 2 and its occupants is m2 = 250kg. (A) Find the acceleration the push gives to each canoe. (B) What is the separation of the canoes after 1.2s of pushing?
Mass The measurement of how much matter is in an object Weight The measurement of how hard the force of gravity is being exerted on an object What would happen to your mass & weight if you traveled to different planets?
Jack and Jill lift upward on a 1.3kg pail of water, with Jack exerting a force F1 of magnitude 7 N and Jill exerting a force F2 of magnitude 11N. Jill s force is exerted at an angle of 28 degrees with the vertical. At what angle with respect to the vertical should Jack exert his force if the pail is to accelerate straight upward?
Two crewmen pull a boat through a lock. One crewman pulls with a force of 130N at an angle od 34 degrees. The second crewman, on the opposite side of the lock, pulls at an angle of 45 degrees. With what force should the second crewman pull so that the net force of the crewmen is the forward direction?
You pull on a sled that has a mass of 4.6kg with 6.2 N of force that is 35 degrees from the horizontal. How fast is it going after 1.5 seconds? With what force do you need to pull on the sled in order for it to come off the ground?
Normal Force - is the component, perpendicular to the surface of contact, of the contact force exerted on an object **Misconception** - Normal Force is not equal and opposite to weight
The fire alarm goes off and a 97 kg fireman slides 3 meters down a pole to the ground floor in 1.2 seconds. What was the upward force exerted by the pole on the fireman? What is the upward force exerted by the fireman if he just hangs on the pole?
Charlie owns a shady donut business in an elevator. Charlie sells donuts by the Newton. If the donuts have a mass of 0.8kg at what point in the elevator ride should you weigh the donuts? (A) What is the weight of the donuts when the elevator starts to go down with an acceleration of 2 m/s^2? (B) What is the weight of the donuts as the elevator is traveling down with a constant speed of 5 m/s? (C) What is the weight of the donuts when the elevator starts to go up with an acceleration of 2 m/s^2?
A jet can be catapulted from 0 to 155 mi/hr (51.4 m/s) in 2 seconds. If the average force exerted is 5.1 x 10^6 N What is the mass of the jet?
As part of a physics experiment, you stand on a bathroom scale in an elevator. Though your normal weight is 610 N, the scale at the moment reads 730N. (A) Is the acceleration of the elevator upward, downward, or zero? Explain. (B) Calculate the magnitude of the elevator s acceleration?
A 23 kg suitcase is being pulled by a handle that is an angle of 25 degrees above the horizontal. If the normal force exerted on the suitcase of 180 N, what is the force applied to the handle?
A 747 jetliner lands and begins to slow to a stop as it moves along the runway. If its mass is 3.5 x 10^5 kg, its speed is 27 m/s. and the net braking force is 4.3 x 10^5 N. (A) What is its speed 7.5s later? (B) How far has it traveled in this time? A 6kg block of ice is acted on by two forces F1 and F2 as shown in the diagram. If the magnitude of F1 = 13N and F2 = 11N, find (A) the acceleration of the ice and (B) The normal force exerted on it by the table.
A 873 kg dragster, starting from rest, attains a speed of 26.3 m/s in 0.59s. What is the magnitude of the force on the dragster during this time? A block of ice is pushed with a force of 40N at an angle of 25 degrees below the horizontal. The block of ice has a mass of 12kg. What is the normal force on the ice block? With what acceleration will the ice block have?