Work
Power
Simple Machines
Laws of Motion
Speed
100
What is the unit for work?
Joules (J)
100
What is the unit for power?
Watt (W)
100
What is an object that changes a force called?
Simple Machine
100
Define the Laws of Motion
Law 1: Objects in motion stay in motion. Objects at rest stay at rest, unless an unbalanced force acts on it. (Inertia)
Law 2: The greater the mass, the greater the force needed to accelerate the object. F=MxA
Law 3: Every action has an equal and opposite reaction
100
Speed is measured using units of what?
Distance and Time
200
How far will 490 J of work raise a block weighing 7 N Hint: w=fxd
Distance=70 meters
200
w= 500 Joules
t = 25 seconds
P = ?
Hint: w=pxt
Power=20W
200
Which simple machine is made up of two inclined planes?
Wedge
200
What is intertia?
The resistance of change in motion
200
________________ is a change in an object’s position compared to objects around it.
Reference Point
300
It took 500 newtons of force to push a car 4 meters. How much work was done? Hint: w=fxd
Work = 2000 Joules
300
How much time is needed to produce 720 Joules of work if 90 watts of power is used? Hint: w=pxt
time=8secs
300
How do simple machines help people work?
Simple machines allow people to do work with less force.
300
How much force is required to accelerate a 15-passenger van weighing 1955 kg at a rate of 26.82 m/s2? Hint: F=MxA
52433.1 N
300
Megan drives a semi-truck at an average speed of 45 mph on a journey of 135 miles. How long did the journey take? Hint: D=SxT
Time= 3 hours
400
Choose all of the following that are doing work:
A scientist delivers a speech to an audience of his peers.
A bodybuilder lifts 350 pounds above his head.
A mother carries her baby from room to room.
A father pushes a baby in a carriage.
A woman carries a 20 kg grocery bag to her car.
A bodybuilder lifts 350 pounds above his head.
A father pushes a baby in a carriage.
400
If 68 W of power is produced in 18 seconds, how much work is done? Hint: w=pxt
Work=1224J
400
Lever
Pulley
Inclined Plane
Wheel and Axle
Screw
Wedge
400
Identify the scenarios as each law
1.Noah jumps down on the diving board and the diving board pushes him up.
2. As Allison jumps rope, each time she jumps she is pulled downward by gravity instead of continuing upwards.
3. Adam can throw a water balloon farther than his little brother.
4. When his sled hits a rock and suddenly stops, Pete continues to move forward.
5. When Jake pushes harder on the ice with his leg muscles, he begins to skate faster.
1. 3rd Law
2. 3rd Law
3. 2nd Law
4. 1st Law
5. 2nd Law
400
Victoria has to travel a total of 21 miles by mule in 4 hours. How fast must she travel? Hint: D=SxT
84 miles/hours
500
Sheila did 110 J of work to move a chair 2 m to the right. How much force did Sheila use to move the chair? Hint: w=fxd
Force=55 N
500
A set of pulleys lifts an 800 N crate 4 meters in 7 seconds. What power was used? Hint: w=pxt and w=fxd
Power=457.14W
500
What is the fixed point that a lever moves on called?
Fulcrum
500
Describe the unbalanced forces within a car that protect you in an accident
Crumple Zone- takes the impact away from your body
Air bag- Also absorbs the impact and protects you
Seat belt- Holds you from your continued motion
500
Based on the graph, What is the speed at 4 meters?
2 m/s