a 50 kg crate is lifted to a height of 10 meters.
a. how much potential energy does the crate have after being lifted?
b. if it took 5 seconds to lift the crate, using a machine what was the power rating of the machine?
a) Work = Force x Distance
The Force in this case is Mass*(acceleration of gravity), so
Work = 50 kg*9.8 m/s^2*10 m = __ Newtons
b) Power = Work/Time
one half second after starting from rest, a free falling oblect will have a speed of about what?
homogeneous mixture
To answer these questions, we can use the principles of potential energy and power.
a. To calculate the potential energy of the crate, we can use the formula:
Potential Energy = mass x gravity x height
where mass is the mass of the crate (50 kg), gravity is the acceleration due to gravity (approximately 9.8 m/s²), and height is the height it was lifted (10 meters).
Potential Energy = 50 kg x 9.8 m/s² x 10 m
Potential Energy = 4900 Joules
Therefore, the crate has a potential energy of 4900 Joules after being lifted.
b. The power rating of the machine can be calculated using the formula:
Power = Work / Time
where Work is the work done to lift the crate and Time is the time taken to lift it.
Work = Potential Energy
Time = 5 seconds
Power = Potential Energy / Time
Power = 4900 Joules / 5 seconds
Power = 980 Watts
Therefore, if it took 5 seconds to lift the crate, the power rating of the machine is 980 Watts.