a warehouse employee is pushing a 38 kg desk across a floor at a constant speed of 0.4 m/s. How much work must the employee do on the desk to change the speed of 1.5m/s?
According to work energy theorem workdone=change in kinetic energy of the body.W=1/2M(V2^2-V1^2)=1/2(38)(1.5^2-0.4^2)=39.71Joules
To determine the work done by the employee to change the speed of the desk, we need to calculate the change in kinetic energy. The work-energy theorem states that the work done is equal to the change in kinetic energy.
The formula for calculating the kinetic energy is:
Kinetic Energy = (1/2) * mass * velocity^2
Given:
Mass of the desk (m) = 38 kg
Initial velocity (v1) = 0.4 m/s
Final velocity (v2) = 1.5 m/s
First, let's calculate the initial kinetic energy of the desk:
Initial Kinetic Energy (KE1) = (1/2) * mass * velocity^2
= (1/2) * 38 kg * (0.4 m/s)^2
Next, let's calculate the final kinetic energy of the desk:
Final Kinetic Energy (KE2) = (1/2) * mass * velocity^2
= (1/2) * 38 kg * (1.5 m/s)^2
The change in kinetic energy (ΔKE) is equal to the final kinetic energy minus the initial kinetic energy:
Change in Kinetic Energy (ΔKE) = KE2 - KE1
Finally, we can calculate the work done by the employee using the work-energy theorem:
Work (W) = ΔKE
Now, let's plug in the values and calculate the work done:
KE1 = (1/2) * 38 kg * (0.4 m/s)^2
KE2 = (1/2) * 38 kg * (1.5 m/s)^2
ΔKE = KE2 - KE1
Therefore, the work done by the employee to change the speed of the desk from 0.4 m/s to 1.5 m/s is equal to the change in kinetic energy, which is ΔKE.