Final answer:
To accelerate the sledgehammer at a rate of 4.0m/s², a person would need to apply a net force of 14 Newtons.
Step-by-step explanation:
To calculate the net force required to accelerate the sledgehammer, you can use Newton's second law of motion, which states that force is equal to mass times acceleration (F = ma). In this case, the mass of the sledgehammer is 3.5 kg and the desired acceleration is 4.0 m/s². Therefore, the net force can be calculated as:
F = (3.5 kg) × (4.0 m/s²) = 14 N
So, a person would need to apply a net force of 14 Newtons to accelerate the sledgehammer at a rate of 4.0 m/s².