The pulley is really a wheel and axle with a rope or chain attached. A pulley makes work seem easier because it changes the direction of motion to work with gravity. Let's say you have to lift a heavy load, like a bale of hay, up to the second floor of a barn. You could tie a rope to the bale of hay, stand on the second floor, and pull it straight up. Or you could put a pulley at the second floor, stand at the first floor, and lift the bale of hay by pulling straight down. It would be the exact amount of work in either case, but the action of pulling down feels easier because you're working with the force of gravity.
A pulley really saves effort when you have more than one pulley working together. By looping a rope around two, three, or even four pulleys, you can really cut down on the effort needed to lift something. The trade-off? Well, as you increase the number of pulleys, you also increase the distance you have to pull the rope. In other words, if you use two pulleys, it takes half the effort to lift something, but you have to pull the rope twice as far. Three pulleys will result in one-third the effort — but the distance you have to pull the rope is tripled!
Answer:
Momentum of bullet
momentum of baseball
Explanation:
As we know that momentum is defined as the product of mass and velocity
here we know that
mass of the bullet = 8 gram
velocity of bullet = 340 m/s
momentum of the bullet is given as
Now we have
mass of baseball = 0.2 kg
velocity of baseball = 40 m/s[/tex]
momentum of baseball is given as
Answer:
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Explanation:
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It is false that scientific advances have led to decreased energy efficiency and waste reduction.
Answer:
11.94
Explanation:
Remark
Find the Potential Energy at the top.
Givens
m = 65 kg
h = 16.2 m
g = 9.81
PE = 65 * 9.81 * 16.2
PE = 10329.93
The tricky part is what do you do about Friction?
Formula
PE = Friction + KE
Solution
PE = 10329.93 Joules
Friction = 5700 Joules
Find the KE
10329.93 = 5700 + KE
KE = 10329.93 - 5700
KE = 4629.93
Find V from the KE formula
KE = 4629.93
m = 65
KE = 1/2 m v^2
KE = 1/2 65 v^2
4629.93 = 1/2 65 v^2
v^2 = 142.46
v = √142.46
v = 11.94
