Speed, Velocity, and Acceleration
What is distance/time?
Speed
What is net force? Which unit is it measured in?
It is the overall force which is exerted on an object, and it is measured in Newtons (N).
What are Newton's three laws of motion in their order?
The 1st Law - An object at rest will remain at rest and an object in motion will remain in motion until acted upon by an unbalanced force. (Law of inertia)
The 2nd Law - The force of an object is equal to its mass multiplied by its acceleration. (Law of acceleration)
The 3rd Law - For every action there is an equal and opposite reaction. (Law of action and reaction)
What is the formula for work? Name all units.
Work (J, joules) = Force (N, newtons) × Distance (m, meter)
What is the formula for power? Name all units.
Power (Watts) = work (joules) / time (sec, hrs, etc.)
What is speed with respect to direction?
Velocity
What is the net force of a BALANCED force? Do they change the position of an object?
They have a net force of 0 N because they cancel each other out; thus, they do not change the position of an object.
A truck with a mass of 6000 kg and a car with a mass of 1500 kg are moving with the same amount of force. Which vehicle will have more acceleration?
The car, which has less mass. (F = ma can be modified to F/m = a; if F stays the same, as m increases, a decreases)
Is a person pushing a box doing work?
Yes
List the 6 simple machines
Wheel and axel, screw, inclined plane, wedge, pulley, lever
What is a change in velocity which is usually measured in m/s2 called?
Acceleration
What are unbalanced forces?
They are forces that cause a change in the position of the object they are exerting force on and have a positive net force.
It would be easier for you to push a 400 kg box than a 4000 kg elephant. This example best illustrates which Newtonian law?
Newton's 2nd Law of Motion
Is a person holding a box doing work?
No
List the simple machine
Lid on a jar
Axe
Ramp
Screw
Wedge
Inclined Plane
What is the velocity of a car which goes 3600 kilometers in 40 hours backwards?
90 km/h
What is the net force exerted on an object with forces of 15 N and 40 N moving it right and a force of 60 N moving it left? In which direction will the object move?
The object will have a net force of 5 N moving left.
When rowing a boat, the boatman pushes the water backwards with the oars. The water exerts an equal and opposite push on the boat, which moves forward. Which Newtonian law does this best demonstrate?
Newton's 3rd Law of Motion
How much work does a person do if they push a cart with a mass of 30 kg across 10 meters with a force of 40 N?
400 J
In a distance time graph, the more steep or the higher the slope of the line, the _____________ the speed is.
faster
What is the acceleration of a ball which has an initial velocity of 0 m/s and a final velocity of 20 m/s over the course of 40 seconds?
0.5 m/s2
Forces of 15 N and 98 N are pushing left on an object, while forces of 53 N and 60 N are pushing right on the object. What is the net force exerted on the object, and are the forces balanced or unbalanced?
The forces are balanced with a net force of 0 N.
If you were in an airplane that is moving at a specific speed and you were to jump in the airplane, you will land at the same spot. Why is this? Which Newtonian Law does this represent?
According to the 1st Law of Motion, an object in motion stays in motion, so you move with the airplane and continue to move at the same rate as the airplane even when you jump.
How much force does a person put into pushing a box 12 meters if they do 396 J of work?
33 N
A new conveyor system at the local packaging plan will utilize a motor-powered mechanical arm to exert an average force of 890 N to push large crates a distance of 12 meters in 22 seconds. Determine the power output required of such a motor.
485.5 W