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:
Explanation:
Range of projectile R = 20 m
formula of range
R = u² sin2θ / g
u is initial velocity , θ is angle of projectile
putting the values
20 = u² sin2x 40 / 9.8
u² = 199
u = 14.10 m /s
At the initial point
vertical component of u
= u sin40 = 14.1 x sin 40
= 9.06 m/s
Horizontal component
= u cos 30
At the final point where the ball strikes the ground after falling , its speed remains the same as that in the beginning .
Horizontal component of velocity
u cos 30
Vertical component
= - u sin 30
= - 9.06 m /s
So its horizontal component remains unchanged .
change in vertical component = 9.06 - ( - 9.06 )
= 18.12 m /s
change in momentum
mass x change in velocity
= .050 x 18.12
= .906 N.s
Impulse = change in momentum
= .906 N.s .
Answer:
If you're asking if this is true or false, the answer is true.
Explanation:
Answer: 2.7 x 10^5 joules
Explanation:
Given that:
Time taken = 3 minutes
convert time in minutes to seconds
(Since 1 minute = 60 seconds
3 minutes = 3 x 60 = 180 seconds)
Power of toaster = 1500 watt
Work done by the toaster = ?
Recall that power is the rate of work done per unit time
i.e Power = work/time
work = Power x Time
Work = 1500 watt x 180 seconds
Work = 270000J
Place the result in standard form
270000J = 2.7 x 10^5J
Thus, 2.7 x 10^5 joules of work is done by the toaster.
Answer:
Option A, Boyle's law
Explanation:
The complete question is
Pressure and volume changes at a constant temperature can be calculated using
a. Boyle's law. c. Kelvin's law.
b. Charles's law. d. Dalton's law.
Solution
In Boyle’s law, the gas is assumed to be ideal gas and at constant temperature. With these two conditions fixed, Boyle’s established that volume of gas varies inversely with the absolute pressure.
The basic mathematical representation of this phenomenon is as follows -
OR
Where P is the pressure of ideal gas, V is the volume and k is the constant of proportionality.
Hence, option A is correct
