## Physics: Principles with Applications (7th Edition)

$1.3 \times 10^{4} N$.
Choose up to be the positive direction. Use Newton’s second law to find the required net force in the vertical direction. $$\Sigma F=F_t – mg = ma$$ $$F_t=m(g+a) = (1200 kg)(9.80 \frac{m}{s^{2}}+0.70 \frac{m}{s^{2}}) \approx 13000 N$$ The answer is rounded to 2 significant figures.