Answer :
Final answer:
The net vertical force acting on the barbell, when considering both the upward force exerted by the weightlifter and the downward gravitational force, is 205.4 N upward.
Explanation:
The question asks to find the net vertical force acting on a barbell that a weightlifter is lifting. The weightlifter exerts a force of 960 N upward against the barbell. To find the net force, we need to consider the force due to gravity acting downward on the barbell as well. The weight of the barbell can be calculated using the formula F = m × g, where m is the mass (77 kg for the barbell) and g is the acceleration due to gravity (approximately 9.8 m/s2). This gives us a force due to gravity on the barbell of 754.6 N (77kg × 9.8m/s2). The net vertical force is therefore the difference between the upward force exerted by the weightlifter and the downward gravitational force, which is 960 N - 754.6 N = 205.4 N upward.
