Question

Pierre lifts a 60-kg crate onto a truck bed 1 m high in 3 s. Marie lifts twenty-four 2.5-kg boxes onto the same truck bed in a time of 2 min. Which of the following statements concerning work and power are true?

Answer 1

Answer:

Pierre operates at a greater power level than Marie.

Marie and Pierre do  the same amount of work

Step-by-step explanation:

Mass of crate=60kg

Height of truck bed=1 m

Time=3s

Pierre's work done=$60\times 1\times 9.8=588J$

Using formula Work done=mgh

Where m=mass of object

g=Acceleration due to gravity=9.8$m/s^2$

Power=$\frac{w}{t}$

Using the formula

Pierre's power=$\frac{588}{3}=196watt$

Mass of box=2.5Kg

Total number of boxes=24

Total mass of boxes=$2.5\times 24=60kg$

Time=2 min=$2\times 60=120s$

1 min=60 s

Marie;s work done=$60\times 1\times 9.8=588J$

Marie's power=$\frac{588}{120}=4.9watt$

Pierre operates at a greater power level than Marie.

Marie and Pierre do  the same amount of work