torque wrench units
2 physics questions relating work and force, please help!!?
Question one:
A group of firemen pumped out a flooded basement.The water is "lifted" to a 2.70m high Gully Road. The motor pump used 54 000Nm of stroke work. How many liters of water were pumped?
Question 2:
The physical sizes of the rotation moment (torque) and work are both very different things, yet are both measured with the unit Newton Meters.
a) in both sizes the amount of force will be multiplied with the lenght, where is the difference between them?
b) calculate the work required when turning a wrench (25cm long) (9cm distance) (F=80N).
c) How big is the work when the screw is rotated (to the same angle) with a 12.5cm (50cm) long wrench
Please explani fully, with words not just numbers, and please make sure you write which equations you are using and why, pretend you are explaining this to a person who has no physical knowledge what so ever. Thank you very muuuch in advance.
Hello
When you lift a mass m up by h meters the change in potential energy is Epot = mgh. And this is equal to the work done.
You are given the work and the height and ask for the mass:
E = mgh
54000 Nm = m*9,81 m/s^2*2,7 m
m = 54000/(9,81*2,7)
m = 2038 kg = 2038 L
Nm as work: Force acts along a certain distance
Nm as torque : Force acts perpendicular to a certain distance, and torque*angle = F*m*θ = work
The wrench of 25 cm length is rotated by 9 cm, --> calculate the angle:
U = 2pir = 157cm, --> 157 cm = 360°, 9 cm = 9*360/157° = 20,6°,
and 20,6° are in radians = 20,6*pi/180 = 0,36 radians.
The work done by thy wrench is W = F*r*θ = 80*0,25*0,36 = 7,2 Nm
When you use a different wrench length, the work will remain the same.
With a doubled length the force will halved, the angle will remain the same.
With a halved length the force will be doubled, the angle will remain the same.
Regards
