A machine of efficiency 80% is used to raise a load of body of mass 75kg through a vertical height of 3m in 30seconds.Calculate the power input.
P = W/t = mgh/t = 75*9.8*3/30
80% eff means divide above by 0.8
E=Work done/txinput x100
80=75*10*3*100/30input
Cross multiply
80x30input =225000
2400input =225000
Input =225000/2400
Input =93.75
An inclined plane of angle 15is used of 2m .if the plane is 75% efficiency calculate the velocity ration of the plane and work done on the load
Yes
Yes that's the question
Well, let's calculate the power input. To do this, we can use the formula:
Power = (Work Done) / (time)
First, we need to calculate the work done. The work done is equal to the force applied (mg) multiplied by the distance moved (height).
Work Done = mg * height
where m is mass and g is the acceleration due to gravity.
Work Done = 75 kg * 9.8 m/s^2 * 3 m
Work Done = 2205 Joules
Now, we can calculate the power input:
Power = Work Done / time
Power = 2205 J / 30 s
Power = 73.5 Watts
So, the power input is approximately 73.5 Watts. However, with 80% efficiency, we would multiply this by 0.8 to get the actual power input.
Actual Power Input = 73.5 W * 0.8
Actual Power Input = 58.8 Watts
So, the actual power input is approximately 58.8 Watts. That's the power of efficiency clowning around!
To calculate the power input, we need to use the formula:
Power = Work done / Time taken
First, let's find the work done.
Work Done = Force x Distance
The force required to lift the load is equal to the weight of the object, which can be calculated using the formula:
Force = Mass x Acceleration due to Gravity
= Mass x 9.8 m/s^2 (standard value for acceleration due to gravity)
So, the force required is:
Force = 75 kg x 9.8 m/s^2
= 735 N
Now, let's calculate the distance:
Distance = 3 m
Next, we need to calculate the work done:
Work Done = Force x Distance
= 735 N x 3 m
= 2205 Nm (Joules)
The time taken is given as 30 seconds.
Now, we can calculate the power input:
Power = Work Done / Time taken
= 2205 Nm / 30 s
= 73.5 W
Therefore, the power input required is 73.5 Watts.