Forces
Work and power
Sir Isaac
Machines
Mechanical advantage
100

Weakest universal force, works over largest distances

gravity

100
Bob pushed a 10kg table 20 meters across the floor with a force of 50N. How much work did Bob do?
100 joules
100
How much force does a truck weighing 1000kg and accelerating at a rate of 3 m/s2 have?
3000N
100
Child 1 = 20kg Child 2 = 40 kg Total length of the see saw =3 m How long do the respective arms of the see saw need to be to make them balance?
2m and 1m
100
What shape wedge produces the greatest mechanical advantage?
longer and thinner
200

1 kg m/s= ?

1 newton

200
If a machine does 400 joules of work to exert 40N of force on an object, how far did it move the object?
10m
200

An object in motion stays in motion until____________

an unbalance force acts on it

200
Wheel radius = .5 m axle radius = .1 m How much force needs to be applied to the wheel to produce 100N of force on the axle?
20N
200

The input arm of the lever is 40 cm and the output arm is 60 cm.  Does the lever increase or decrease the amount of force needed to lift the object?

Increase

300

Air resistance is an example of what type of friction? 

Fluid friction

300
How much power does a machine that can do 500joules of work in 10 seconds have?
50 watts
300

Which has more momentum, a 50kg roller skater traveling at a speed of 3m/s or an 80kg bicyclist traveling 2m/s?

bicyclist

300
How many pulleys are needed to allow a 100kg person to use only their body weight to lift a 1000kg vehicle?
10
300
The input arm of a lever is 30cm and the output arm is 10 cm.  How much force would you need to apply to lift a 15kg object?
5kg
400

What is the net force applied to the box?


-

400
What are two ways that one could increase their power?
Increase the amount of work done in a given time or decrease the time necessary to complete a given amount of work.
400

A train car weighing 1000kg and traveling 2m/s bumps into a stationary train car of the same size. They stick together and continue moving. What speed are they moving at?

1 m/s

400

A person can exert 200N of force on an object that weighs 1000N. How long a ramp would they need to have to successfully raise the object to a height of 1 M?

5 m

400

A compound machine includes the following components:

ramp with a mechanical advantage of 3

3 pulleys

Wheel and axle with a mechanical advantage of 5

What is the total MA of the machine?

45

500

What forces hold the nuclei of atoms together?

Nuclear forces

500

Which is more powerful, a 2 horsepower engine or a 400 watt motor?

2 hp (1500 watts)

500

How can you reduce the impulse of a collision?

increase the collision time 

reduce the speed of the object

500

A machine has an IMA of 8 and an AMA of 6.  What is it's efficeincy?

75%

500

What is the total mechanical advantage of a 1 meter ramp and 3 pulleys that raise an object to a height of .5 meters.  

6

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