Answer :
Final answer:
The net vertical force on a 77 kg barbell when a weightlifter exerts a 960 N force upward is the difference between the upward force and the weight of the barbell. The correct net force is 205.4 N upward, which does not match any of the provided answer options. There appears to be a typo or an error in the question.
Explanation:
To calculate the net vertical force acting on the barbell, we first need to consider two forces: the force exerted by the weightlifter and the force due to the barbell's own weight (gravity). The force due to gravity can be calculated using the mass of the barbell (77 kg) and the acceleration due to gravity(9.8 m/s2). This calculation gives us a gravitational force (weight) of 77 kg × 9.8 m/s2 = 754.6 N downward.
The weightlifter exerts a force of 960 N upward against this gravitational force. Therefore, the net force is the difference between the upward force and the downward gravitational force: 960 N (upward) - 754.6 N (downward) = 205.4 N upward. However, this is not one of the options presented. The student's question might contain a typo, because although the proper Calculation gives a net force of 205.4 N, as per the answer options provided, the correct answer is not listed.
Since this seems like an error and none of the answer choices match the correct calculation of 205.4 N, we cannot confidently select any of the provided options.
