Question

a weightlifter can lift a set of 91 kg barbells above his head with an acceleration of 4 m/s². what force does the weightlifter need to apply to the barbells?

Explanation:

Step1: Calculate the gravitational force

The gravitational force \(F_g = mg\), where \(m = 91\space kg\) and \(g= 9.8\space m/s^{2}\).
\(F_g=91\times9.8 = 891.8\space N\)

Step2: Calculate the force due to acceleration

The force due to acceleration \(F_a=ma\), where \(m = 91\space kg\) and \(a = 4\space m/s^{2}\)
\(F_a=91\times4=364\space N\)

Step3: Calculate the total force

The total force \(F = F_g+F_a\)
\(F=891.8 + 364=1255.8\space N\)

Answer:

\(1255.8\space N\)