Question

Example 1: Two physics students, Ben and Bonnie, are in the weightlifting room. Bonnie lifts the 50kg barbell
over her head (approximately .60 m) 10 times in one minute; Ben lifts the 50 kg barbell the same distance over his
head 10 times in 10 seconds.
o Which student does the most work?
O
Which student delivers the most power?

Answer 1

Answer:

Same

Ben.

Explanation:

m = Mass Bonnie and Ben lift = 50 kg

s = Displacement of mass by both the students = 0.6 m

Work done by both the student is

$W=Fs\\\Rightarrow W=10\times 50\times 0.6\\\Rightarrow W=300\ \text{J}$

The amount of work done by both the students will be equal to 300 J.

$t_1$ = Time taken by Bonnie = 1 minute = 60 seconds

$t_2$ = Time taken by Ben = 10 seconds.

Power delivered by Bonnie

$P=\dfrac{W}{t_1}\\\Rightarrow P=\dfrac{300}{60}\\\Rightarrow P=5\ \text{W}$

Power delivered by Ben

$P=\dfrac{W}{t_2}\\\Rightarrow P=\dfrac{300}{10}\\\Rightarrow P=30\ \text{W}$

So, power delivered by Ben is more.