a forklift lifts a 100 kg of concrete through a vertical height of 16 m in 20 sec.the power applied to the motor un driving the forklift is 1kw.a) calculate the work done every second in lifting the concrete block.b) what is the power output of the motor?c) what is the efficiency of the motor?
Fc = M*g = 100 * 9.8 = 980 N.
a. Work/s = F*d/t = 980 * 16/20 = 784 J./s. = 784 Watts.
b. Po = Work/s = 784 J/s.
c. Efficiency = Po/Pi = 784Watts/1000Watts = 0.784 = 78.4%.
To calculate the work done every second in lifting the concrete block, we can use the formula:
Work = Force × Distance
The force required to lift the concrete block can be determined using the equation:
Force = Mass × Acceleration
Acceleration due to gravity is approximately 9.8 m/s^2. Therefore, the force required to lift a 100 kg object against gravity is:
Force = Mass × Acceleration
= 100 kg × 9.8 m/s^2
= 980 N
Now, to calculate the work done every second, we need to find the distance covered per second. Given that the concrete block is lifted through a vertical height of 16 m in 20 sec, the distance covered per second is:
Distance per second = Total distance / Total time
= 16 m / 20 sec
= 0.8 m/s
Now we can calculate the work done every second:
Work per second = Force × Distance per second
= 980 N × 0.8 m/s
= 784 J/s
Therefore, the work done every second in lifting the concrete block is 784 Joules per second (J/s), which is equivalent to 784 Watts (W).
Moving on to the next part,
The power output of the motor can be calculated using the equation:
Power = Work done / Time
The work done in lifting the concrete block is already determined as 784 Joules per second. The time taken, as mentioned, is 20 seconds. Therefore, the power output of the motor is:
Power output = Work done / Time
= 784 J/s / 20 s
= 39.2 Watts (W)
Hence, the power output of the motor is 39.2 Watts (W).
Finally, to calculate the efficiency of the motor, we can use the formula:
Efficiency = (Useful power output / Power input) × 100
The useful power output is the power output of the motor, which is 39.2 Watts (W). The power input is given as 1 kW (kilowatt), but we need to convert it to Watts:
Power input = 1 kW × 1000 W/kW
= 1000 Watts (W)
Now we can calculate the efficiency of the motor:
Efficiency = (Useful power output / Power input) × 100
= (39.2 W / 1000 W) × 100
= 3.92%
Therefore, the efficiency of the motor is approximately 3.92%.